Import aom library

This is the reference implementation for the Alliance for Open Media's av1 video code.

The commit used was 4d668d7feb1f8abd809d1bca0418570a7f142a36.

1 files changed, 1556 insertions, 0 deletions

diff --git a/third_party/aom/build/make/configure.sh b/third_party/aom/build/make/configure.sh
new file mode 100644
index 000000000..4ece17aee
--- /dev/null
+++ b/third_party/aom/build/make/configure.sh
@@ -0,0 +1,1556 @@
+#!/bin/sh
+##
+##  configure.sh
+##
+##  This script is sourced by the main configure script and contains
+##  utility functions and other common bits that aren't strictly libaom
+##  related.
+##
+##  This build system is based in part on the FFmpeg configure script.
+##
+
+
+#
+# Logging / Output Functions
+#
+die_unknown(){
+  echo "Unknown option \"$1\"."
+  echo "See $0 --help for available options."
+  clean_temp_files
+  exit 1
+}
+
+die() {
+  echo "$@"
+  echo
+  echo "Configuration failed. This could reflect a misconfiguration of your"
+  echo "toolchains, improper options selected, or another problem. If you"
+  echo "don't see any useful error messages above, the next step is to look"
+  echo "at the configure error log file ($logfile) to determine what"
+  echo "configure was trying to do when it died."
+  clean_temp_files
+  exit 1
+}
+
+log(){
+  echo "$@" >>$logfile
+}
+
+log_file(){
+  log BEGIN $1
+  cat -n $1 >>$logfile
+  log END $1
+}
+
+log_echo() {
+  echo "$@"
+  log "$@"
+}
+
+fwrite () {
+  outfile=$1
+  shift
+  echo "$@" >> ${outfile}
+}
+
+show_help_pre(){
+  for opt in ${CMDLINE_SELECT}; do
+    opt2=`echo $opt | sed -e 's;_;-;g'`
+    if enabled $opt; then
+      eval "toggle_${opt}=\"--disable-${opt2}\""
+    else
+      eval "toggle_${opt}=\"--enable-${opt2} \""
+    fi
+  done
+
+  cat <<EOF
+Usage: configure [options]
+Options:
+
+Build options:
+  --help                      print this message
+  --log=yes|no|FILE           file configure log is written to [config.log]
+  --target=TARGET             target platform tuple [generic-gnu]
+  --cpu=CPU                   optimize for a specific cpu rather than a family
+  --extra-cflags=ECFLAGS      add ECFLAGS to CFLAGS [$CFLAGS]
+  --extra-cxxflags=ECXXFLAGS  add ECXXFLAGS to CXXFLAGS [$CXXFLAGS]
+  ${toggle_extra_warnings}    emit harmless warnings (always non-fatal)
+  ${toggle_werror}            treat warnings as errors, if possible
+                              (not available with all compilers)
+  ${toggle_optimizations}     turn on/off compiler optimization flags
+  ${toggle_pic}               turn on/off Position Independent Code
+  ${toggle_ccache}            turn on/off compiler cache
+  ${toggle_debug}             enable/disable debug mode
+  ${toggle_gprof}             enable/disable gprof profiling instrumentation
+  ${toggle_gcov}              enable/disable gcov coverage instrumentation
+  ${toggle_thumb}             enable/disable building arm assembly in thumb mode
+  ${toggle_dependency_tracking}
+                              disable to speed up one-time build
+
+Install options:
+  ${toggle_install_docs}      control whether docs are installed
+  ${toggle_install_bins}      control whether binaries are installed
+  ${toggle_install_libs}      control whether libraries are installed
+  ${toggle_install_srcs}      control whether sources are installed
+
+
+EOF
+}
+
+show_help_post(){
+  cat <<EOF
+
+
+NOTES:
+    Object files are built at the place where configure is launched.
+
+    All boolean options can be negated. The default value is the opposite
+    of that shown above. If the option --disable-foo is listed, then
+    the default value for foo is enabled.
+
+Supported targets:
+EOF
+  show_targets ${all_platforms}
+  echo
+  exit 1
+}
+
+show_targets() {
+  while [ -n "$*" ]; do
+    if [ "${1%%-*}" = "${2%%-*}" ]; then
+      if [ "${2%%-*}" = "${3%%-*}" ]; then
+        printf "    %-24s %-24s %-24s\n" "$1" "$2" "$3"
+        shift; shift; shift
+      else
+        printf "    %-24s %-24s\n" "$1" "$2"
+        shift; shift
+      fi
+    else
+      printf "    %-24s\n" "$1"
+      shift
+    fi
+  done
+}
+
+show_help() {
+  show_help_pre
+  show_help_post
+}
+
+#
+# List Processing Functions
+#
+set_all(){
+  value=$1
+  shift
+  for var in $*; do
+    eval $var=$value
+  done
+}
+
+is_in(){
+  value=$1
+  shift
+  for var in $*; do
+    [ $var = $value ] && return 0
+  done
+  return 1
+}
+
+add_cflags() {
+  CFLAGS="${CFLAGS} $@"
+  CXXFLAGS="${CXXFLAGS} $@"
+}
+
+add_cflags_only() {
+  CFLAGS="${CFLAGS} $@"
+}
+
+add_cxxflags_only() {
+  CXXFLAGS="${CXXFLAGS} $@"
+}
+
+add_ldflags() {
+  LDFLAGS="${LDFLAGS} $@"
+}
+
+add_asflags() {
+  ASFLAGS="${ASFLAGS} $@"
+}
+
+add_extralibs() {
+  extralibs="${extralibs} $@"
+}
+
+#
+# Boolean Manipulation Functions
+#
+
+enable_feature(){
+  set_all yes $*
+}
+
+disable_feature(){
+  set_all no $*
+}
+
+enabled(){
+  eval test "x\$$1" = "xyes"
+}
+
+disabled(){
+  eval test "x\$$1" = "xno"
+}
+
+enable_codec(){
+  enabled "${1}" || echo "  enabling ${1}"
+  enable_feature "${1}"
+
+  is_in "${1}" av1 && enable_feature "${1}_encoder" "${1}_decoder"
+}
+
+disable_codec(){
+  disabled "${1}" || echo "  disabling ${1}"
+  disable_feature "${1}"
+
+  is_in "${1}" av1 && disable_feature "${1}_encoder" "${1}_decoder"
+}
+
+# Iterates through positional parameters, checks to confirm the parameter has
+# not been explicitly (force) disabled, and enables the setting controlled by
+# the parameter when the setting is not disabled.
+# Note: Does NOT alter RTCD generation options ($RTCD_OPTIONS).
+soft_enable() {
+  for var in $*; do
+    if ! disabled $var; then
+      enabled $var || log_echo "  enabling $var"
+      enable_feature $var
+    fi
+  done
+}
+
+# Iterates through positional parameters, checks to confirm the parameter has
+# not been explicitly (force) enabled, and disables the setting controlled by
+# the parameter when the setting is not enabled.
+# Note: Does NOT alter RTCD generation options ($RTCD_OPTIONS).
+soft_disable() {
+  for var in $*; do
+    if ! enabled $var; then
+      disabled $var || log_echo "  disabling $var"
+      disable_feature $var
+    fi
+  done
+}
+
+#
+# Text Processing Functions
+#
+toupper(){
+  echo "$@" | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
+}
+
+tolower(){
+  echo "$@" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz
+}
+
+#
+# Temporary File Functions
+#
+source_path=${0%/*}
+enable_feature source_path_used
+if [ -z "$source_path" ] || [ "$source_path" = "." ]; then
+  source_path="`pwd`"
+  disable_feature source_path_used
+fi
+
+if test ! -z "$TMPDIR" ; then
+  TMPDIRx="${TMPDIR}"
+elif test ! -z "$TEMPDIR" ; then
+  TMPDIRx="${TEMPDIR}"
+else
+  TMPDIRx="/tmp"
+fi
+RAND=$(awk 'BEGIN { srand(); printf "%d\n",(rand() * 32768)}')
+TMP_H="${TMPDIRx}/aom-conf-$$-${RAND}.h"
+TMP_C="${TMPDIRx}/aom-conf-$$-${RAND}.c"
+TMP_CC="${TMPDIRx}/aom-conf-$$-${RAND}.cc"
+TMP_O="${TMPDIRx}/aom-conf-$$-${RAND}.o"
+TMP_X="${TMPDIRx}/aom-conf-$$-${RAND}.x"
+TMP_ASM="${TMPDIRx}/aom-conf-$$-${RAND}.asm"
+
+clean_temp_files() {
+  rm -f ${TMP_C} ${TMP_CC} ${TMP_H} ${TMP_O} ${TMP_X} ${TMP_ASM}
+  enabled gcov && rm -f ${TMP_C%.c}.gcno ${TMP_CC%.cc}.gcno
+}
+
+#
+# Toolchain Check Functions
+#
+check_cmd() {
+  enabled external_build && return
+  log "$@"
+  "$@" >>${logfile} 2>&1
+}
+
+check_cc() {
+  log check_cc "$@"
+  cat >${TMP_C}
+  log_file ${TMP_C}
+  check_cmd ${CC} ${CFLAGS} "$@" -c -o ${TMP_O} ${TMP_C}
+}
+
+check_cxx() {
+  log check_cxx "$@"
+  cat >${TMP_CC}
+  log_file ${TMP_CC}
+  check_cmd ${CXX} ${CXXFLAGS} "$@" -c -o ${TMP_O} ${TMP_CC}
+}
+
+check_cpp() {
+  log check_cpp "$@"
+  cat > ${TMP_C}
+  log_file ${TMP_C}
+  check_cmd ${CC} ${CFLAGS} "$@" -E -o ${TMP_O} ${TMP_C}
+}
+
+check_ld() {
+  log check_ld "$@"
+  check_cc $@ \
+    && check_cmd ${LD} ${LDFLAGS} "$@" -o ${TMP_X} ${TMP_O} ${extralibs}
+}
+
+check_header(){
+  log check_header "$@"
+  header=$1
+  shift
+  var=`echo $header | sed 's/[^A-Za-z0-9_]/_/g'`
+  disable_feature $var
+  check_cpp "$@" <<EOF && enable_feature $var
+#include "$header"
+int x;
+EOF
+}
+
+check_cflags() {
+ log check_cflags "$@"
+ check_cc -Werror "$@" <<EOF
+int x;
+EOF
+}
+
+check_cxxflags() {
+  log check_cxxflags "$@"
+
+  # Catch CFLAGS that trigger CXX warnings
+  case "$CXX" in
+    *c++-analyzer|*clang++|*g++*)
+      check_cxx -Werror "$@" <<EOF
+int x;
+EOF
+      ;;
+    *)
+      check_cxx -Werror "$@" <<EOF
+int x;
+EOF
+      ;;
+    esac
+}
+
+check_add_cflags() {
+  check_cxxflags "$@" && add_cxxflags_only "$@"
+  check_cflags "$@" && add_cflags_only "$@"
+}
+
+check_add_cxxflags() {
+  check_cxxflags "$@" && add_cxxflags_only "$@"
+}
+
+check_add_asflags() {
+  log add_asflags "$@"
+  add_asflags "$@"
+}
+
+check_add_ldflags() {
+  log add_ldflags "$@"
+  add_ldflags "$@"
+}
+
+check_asm_align() {
+  log check_asm_align "$@"
+  cat >${TMP_ASM} <<EOF
+section .rodata
+align 16
+EOF
+  log_file ${TMP_ASM}
+  check_cmd ${AS} ${ASFLAGS} -o ${TMP_O} ${TMP_ASM}
+  readelf -WS ${TMP_O} >${TMP_X}
+  log_file ${TMP_X}
+  if ! grep -q '\.rodata .* 16$' ${TMP_X}; then
+    die "${AS} ${ASFLAGS} does not support section alignment (nasm <=2.08?)"
+  fi
+}
+
+# tests for -m$1 toggling the feature given in $2. If $2 is empty $1 is used.
+check_gcc_machine_option() {
+  opt="$1"
+  feature="$2"
+  [ -n "$feature" ] || feature="$opt"
+
+  if enabled gcc && ! disabled "$feature" && ! check_cflags "-m$opt"; then
+    RTCD_OPTIONS="${RTCD_OPTIONS}--disable-$feature "
+  else
+    soft_enable "$feature"
+  fi
+}
+
+write_common_config_banner() {
+  print_webm_license config.mk "##" ""
+  echo '# This file automatically generated by configure. Do not edit!' >> config.mk
+  echo "TOOLCHAIN := ${toolchain}" >> config.mk
+
+  case ${toolchain} in
+    *-linux-rvct)
+      echo "ALT_LIBC := ${alt_libc}" >> config.mk
+      ;;
+  esac
+}
+
+write_common_config_targets() {
+  for t in ${all_targets}; do
+    if enabled ${t}; then
+      if enabled child; then
+        fwrite config.mk "ALL_TARGETS += ${t}-${toolchain}"
+      else
+        fwrite config.mk "ALL_TARGETS += ${t}"
+      fi
+    fi
+    true;
+  done
+  true
+}
+
+write_common_target_config_mk() {
+  saved_CC="${CC}"
+  saved_CXX="${CXX}"
+  enabled ccache && CC="ccache ${CC}"
+  enabled ccache && CXX="ccache ${CXX}"
+  print_webm_license $1 "##" ""
+
+  cat >> $1 << EOF
+# This file automatically generated by configure. Do not edit!
+SRC_PATH="$source_path"
+SRC_PATH_BARE=$source_path
+BUILD_PFX=${BUILD_PFX}
+TOOLCHAIN=${toolchain}
+ASM_CONVERSION=${asm_conversion_cmd:-${source_path}/build/make/ads2gas.pl}
+GEN_VCPROJ=${gen_vcproj_cmd}
+MSVS_ARCH_DIR=${msvs_arch_dir}
+
+CC=${CC}
+CXX=${CXX}
+AR=${AR}
+LD=${LD}
+AS=${AS}
+STRIP=${STRIP}
+NM=${NM}
+
+CFLAGS  = ${CFLAGS}
+CXXFLAGS  = ${CXXFLAGS}
+ARFLAGS = crs\$(if \$(quiet),,v)
+LDFLAGS = ${LDFLAGS}
+ASFLAGS = ${ASFLAGS}
+extralibs = ${extralibs}
+AS_SFX    = ${AS_SFX:-.asm}
+EXE_SFX   = ${EXE_SFX}
+VCPROJ_SFX = ${VCPROJ_SFX}
+RTCD_OPTIONS = ${RTCD_OPTIONS}
+WX_CXXFLAGS = ${WX_CXXFLAGS}
+WX_LDFLAGS = ${WX_LDFLAGS}
+EOF
+
+  if enabled rvct; then cat >> $1 << EOF
+fmt_deps = sed -e 's;^__image.axf;\${@:.d=.o} \$@;' #hide
+EOF
+  else cat >> $1 << EOF
+fmt_deps = sed -e 's;^\([a-zA-Z0-9_]*\)\.o;\${@:.d=.o} \$@;'
+EOF
+  fi
+
+  print_config_mk ARCH   "${1}" ${ARCH_LIST}
+  print_config_mk HAVE   "${1}" ${HAVE_LIST}
+  print_config_mk CONFIG "${1}" ${CONFIG_LIST}
+  print_config_mk HAVE   "${1}" gnu_strip
+
+  enabled msvs && echo "CONFIG_VS_VERSION=${vs_version}" >> "${1}"
+
+  CC="${saved_CC}"
+  CXX="${saved_CXX}"
+}
+
+write_common_target_config_h() {
+  print_webm_license ${TMP_H} "/*" " */"
+  cat >> ${TMP_H} << EOF
+/* This file automatically generated by configure. Do not edit! */
+#ifndef AOM_CONFIG_H
+#define AOM_CONFIG_H
+#define RESTRICT    ${RESTRICT}
+#define INLINE      ${INLINE}
+EOF
+  print_config_h ARCH   "${TMP_H}" ${ARCH_LIST}
+  print_config_h HAVE   "${TMP_H}" ${HAVE_LIST}
+  print_config_h CONFIG "${TMP_H}" ${CONFIG_LIST}
+  print_config_vars_h   "${TMP_H}" ${VAR_LIST}
+  echo "#endif /* AOM_CONFIG_H */" >> ${TMP_H}
+  mkdir -p `dirname "$1"`
+  cmp "$1" ${TMP_H} >/dev/null 2>&1 || mv ${TMP_H} "$1"
+}
+
+process_common_cmdline() {
+  for opt in "$@"; do
+    optval="${opt#*=}"
+    case "$opt" in
+      --child)
+        enable_feature child
+        ;;
+      --log*)
+        logging="$optval"
+        if ! disabled logging ; then
+          enabled logging || logfile="$logging"
+        else
+          logfile=/dev/null
+        fi
+        ;;
+      --target=*)
+        toolchain="${toolchain:-${optval}}"
+        ;;
+      --force-target=*)
+        toolchain="${toolchain:-${optval}}"
+        enable_feature force_toolchain
+        ;;
+      --cpu=*)
+        tune_cpu="$optval"
+        ;;
+      --extra-cflags=*)
+        extra_cflags="${optval}"
+        ;;
+      --extra-cxxflags=*)
+        extra_cxxflags="${optval}"
+        ;;
+      --enable-?*|--disable-?*)
+        eval `echo "$opt" | sed 's/--/action=/;s/-/ option=/;s/-/_/g'`
+        if is_in ${option} ${ARCH_EXT_LIST}; then
+          [ $action = "disable" ] && RTCD_OPTIONS="${RTCD_OPTIONS}--disable-${option} "
+        elif [ $action = "disable" ] && ! disabled $option ; then
+          is_in ${option} ${CMDLINE_SELECT} || die_unknown $opt
+          log_echo "  disabling $option"
+        elif [ $action = "enable" ] && ! enabled $option ; then
+          is_in ${option} ${CMDLINE_SELECT} || die_unknown $opt
+          log_echo "  enabling $option"
+        fi
+        ${action}_feature $option
+        ;;
+      --require-?*)
+        eval `echo "$opt" | sed 's/--/action=/;s/-/ option=/;s/-/_/g'`
+        if is_in ${option} ${ARCH_EXT_LIST}; then
+            RTCD_OPTIONS="${RTCD_OPTIONS}${opt} "
+        else
+            die_unknown $opt
+        fi
+        ;;
+      --force-enable-?*|--force-disable-?*)
+        eval `echo "$opt" | sed 's/--force-/action=/;s/-/ option=/;s/-/_/g'`
+        ${action}_feature $option
+        ;;
+      --libc=*)
+        [ -d "${optval}" ] || die "Not a directory: ${optval}"
+        disable_feature builtin_libc
+        alt_libc="${optval}"
+        ;;
+      --as=*)
+        [ "${optval}" = yasm ] || [ "${optval}" = nasm ] \
+          || [ "${optval}" = auto ] \
+          || die "Must be yasm, nasm or auto: ${optval}"
+        alt_as="${optval}"
+        ;;
+      --size-limit=*)
+        w="${optval%%x*}"
+        h="${optval##*x}"
+        VAR_LIST="DECODE_WIDTH_LIMIT ${w} DECODE_HEIGHT_LIMIT ${h}"
+        [ ${w} -gt 0 ] && [ ${h} -gt 0 ] || die "Invalid size-limit: too small."
+        [ ${w} -lt 65536 ] && [ ${h} -lt 65536 ] \
+            || die "Invalid size-limit: too big."
+        enable_feature size_limit
+        ;;
+      --prefix=*)
+        prefix="${optval}"
+        ;;
+      --libdir=*)
+        libdir="${optval}"
+        ;;
+      --sdk-path=*)
+        [ -d "${optval}" ] || die "Not a directory: ${optval}"
+        sdk_path="${optval}"
+        ;;
+      --libc|--as|--prefix|--libdir|--sdk-path)
+        die "Option ${opt} requires argument"
+        ;;
+      --help|-h)
+        show_help
+        ;;
+      *)
+        die_unknown $opt
+        ;;
+    esac
+  done
+}
+
+process_cmdline() {
+  for opt do
+    optval="${opt#*=}"
+    case "$opt" in
+      *)
+        process_common_cmdline $opt
+        ;;
+    esac
+  done
+}
+
+post_process_common_cmdline() {
+  prefix="${prefix:-/usr/local}"
+  prefix="${prefix%/}"
+  libdir="${libdir:-${prefix}/lib}"
+  libdir="${libdir%/}"
+  if [ "${libdir#${prefix}}" = "${libdir}" ]; then
+    die "Libdir ${libdir} must be a subdirectory of ${prefix}"
+  fi
+}
+
+post_process_cmdline() {
+  true;
+}
+
+setup_gnu_toolchain() {
+  CC=${CC:-${CROSS}gcc}
+  CXX=${CXX:-${CROSS}g++}
+  AR=${AR:-${CROSS}ar}
+  LD=${LD:-${CROSS}${link_with_cc:-ld}}
+  AS=${AS:-${CROSS}as}
+  STRIP=${STRIP:-${CROSS}strip}
+  NM=${NM:-${CROSS}nm}
+  AS_SFX=.s
+  EXE_SFX=
+}
+
+# Reliably find the newest available Darwin SDKs. (Older versions of
+# xcrun don't support --show-sdk-path.)
+show_darwin_sdk_path() {
+  xcrun --sdk $1 --show-sdk-path 2>/dev/null ||
+    xcodebuild -sdk $1 -version Path 2>/dev/null
+}
+
+# Print the major version number of the Darwin SDK specified by $1.
+show_darwin_sdk_major_version() {
+  xcrun --sdk $1 --show-sdk-version 2>/dev/null | cut -d. -f1
+}
+
+# Print the Xcode version.
+show_xcode_version() {
+  xcodebuild -version | head -n1 | cut -d' ' -f2
+}
+
+# Fails when Xcode version is less than 6.3.
+check_xcode_minimum_version() {
+  xcode_major=$(show_xcode_version | cut -f1 -d.)
+  xcode_minor=$(show_xcode_version | cut -f2 -d.)
+  xcode_min_major=6
+  xcode_min_minor=3
+  if [ ${xcode_major} -lt ${xcode_min_major} ]; then
+    return 1
+  fi
+  if [ ${xcode_major} -eq ${xcode_min_major} ] \
+    && [ ${xcode_minor} -lt ${xcode_min_minor} ]; then
+    return 1
+  fi
+}
+
+process_common_toolchain() {
+  case "$toolchain" in
+    *-vs*) ;;
+    *) add_cflags_only -std=c99 ;;
+  esac
+
+  if [ -z "$toolchain" ]; then
+    gcctarget="${CHOST:-$(gcc -dumpmachine 2> /dev/null)}"
+
+    # detect tgt_isa
+    case "$gcctarget" in
+      aarch64*)
+        tgt_isa=arm64
+        ;;
+      armv6*)
+        tgt_isa=armv6
+        ;;
+      armv7*-hardfloat* | armv7*-gnueabihf | arm-*-gnueabihf)
+        tgt_isa=armv7
+        float_abi=hard
+        ;;
+      armv7*)
+        tgt_isa=armv7
+        float_abi=softfp
+        ;;
+      *x86_64*|*amd64*)
+        tgt_isa=x86_64
+        ;;
+      *i[3456]86*)
+        tgt_isa=x86
+        ;;
+      *sparc*)
+        tgt_isa=sparc
+        ;;
+    esac
+
+    # detect tgt_os
+    case "$gcctarget" in
+      *darwin10*)
+        tgt_isa=x86_64
+        tgt_os=darwin10
+        ;;
+      *darwin11*)
+        tgt_isa=x86_64
+        tgt_os=darwin11
+        ;;
+      *darwin12*)
+        tgt_isa=x86_64
+        tgt_os=darwin12
+        ;;
+      *darwin13*)
+        tgt_isa=x86_64
+        tgt_os=darwin13
+        ;;
+      *darwin14*)
+        tgt_isa=x86_64
+        tgt_os=darwin14
+        ;;
+      *darwin15*)
+        tgt_isa=x86_64
+        tgt_os=darwin15
+        ;;
+       *darwin16*)
+        tgt_isa=x86_64
+        tgt_os=darwin16
+        ;;
+      x86_64*mingw32*)
+        tgt_os=win64
+        ;;
+      *mingw32*|*cygwin*)
+        [ -z "$tgt_isa" ] && tgt_isa=x86
+        tgt_os=win32
+        ;;
+      *linux*|*bsd*)
+        tgt_os=linux
+        ;;
+      *solaris2.10)
+        tgt_os=solaris
+        ;;
+      *os2*)
+        tgt_os=os2
+        ;;
+    esac
+
+    if [ -n "$tgt_isa" ] && [ -n "$tgt_os" ]; then
+      toolchain=${tgt_isa}-${tgt_os}-gcc
+    fi
+  fi
+
+  toolchain=${toolchain:-generic-gnu}
+
+  is_in ${toolchain} ${all_platforms} || enabled force_toolchain \
+    || die "Unrecognized toolchain '${toolchain}'"
+
+  enabled child || log_echo "Configuring for target '${toolchain}'"
+
+  #
+  # Set up toolchain variables
+  #
+  tgt_isa=$(echo ${toolchain} | awk 'BEGIN{FS="-"}{print $1}')
+  tgt_os=$(echo ${toolchain} | awk 'BEGIN{FS="-"}{print $2}')
+  tgt_cc=$(echo ${toolchain} | awk 'BEGIN{FS="-"}{print $3}')
+
+  # Mark the specific ISA requested as enabled
+  soft_enable ${tgt_isa}
+  enable_feature ${tgt_os}
+  enable_feature ${tgt_cc}
+
+  # Enable the architecture family
+  case ${tgt_isa} in
+    arm*)
+      enable_feature arm
+      ;;
+    mips*)
+      enable_feature mips
+      ;;
+  esac
+
+  # PIC is probably what we want when building shared libs
+  enabled shared && soft_enable pic
+
+  # Minimum iOS version for all target platforms (darwin and iphonesimulator).
+  # Shared library framework builds are only possible on iOS 8 and later.
+  if enabled shared; then
+    IOS_VERSION_OPTIONS="--enable-shared"
+    IOS_VERSION_MIN="8.0"
+  else
+    IOS_VERSION_OPTIONS=""
+    IOS_VERSION_MIN="6.0"
+  fi
+
+  # Handle darwin variants. Newer SDKs allow targeting older
+  # platforms, so use the newest one available.
+  case ${toolchain} in
+    arm*-darwin*)
+      add_cflags "-miphoneos-version-min=${IOS_VERSION_MIN}"
+      iphoneos_sdk_dir="$(show_darwin_sdk_path iphoneos)"
+      if [ -d "${iphoneos_sdk_dir}" ]; then
+        add_cflags  "-isysroot ${iphoneos_sdk_dir}"
+        add_ldflags "-isysroot ${iphoneos_sdk_dir}"
+      fi
+      ;;
+    x86*-darwin*)
+      osx_sdk_dir="$(show_darwin_sdk_path macosx)"
+      if [ -d "${osx_sdk_dir}" ]; then
+        add_cflags  "-isysroot ${osx_sdk_dir}"
+        add_ldflags "-isysroot ${osx_sdk_dir}"
+      fi
+      ;;
+  esac
+
+  case ${toolchain} in
+    *-darwin8-*)
+      add_cflags  "-mmacosx-version-min=10.4"
+      add_ldflags "-mmacosx-version-min=10.4"
+      ;;
+    *-darwin9-*)
+      add_cflags  "-mmacosx-version-min=10.5"
+      add_ldflags "-mmacosx-version-min=10.5"
+      ;;
+    *-darwin10-*)
+      add_cflags  "-mmacosx-version-min=10.6"
+      add_ldflags "-mmacosx-version-min=10.6"
+      ;;
+    *-darwin11-*)
+      add_cflags  "-mmacosx-version-min=10.7"
+      add_ldflags "-mmacosx-version-min=10.7"
+      ;;
+    *-darwin12-*)
+      add_cflags  "-mmacosx-version-min=10.8"
+      add_ldflags "-mmacosx-version-min=10.8"
+      ;;
+    *-darwin13-*)
+      add_cflags  "-mmacosx-version-min=10.9"
+      add_ldflags "-mmacosx-version-min=10.9"
+      ;;
+    *-darwin14-*)
+      add_cflags  "-mmacosx-version-min=10.10"
+      add_ldflags "-mmacosx-version-min=10.10"
+      ;;
+    *-darwin15-*)
+      add_cflags  "-mmacosx-version-min=10.11"
+      add_ldflags "-mmacosx-version-min=10.11"
+      ;;
+    *-darwin16-*)
+      add_cflags  "-mmacosx-version-min=10.12"
+      add_ldflags "-mmacosx-version-min=10.12"
+      ;;
+    *-iphonesimulator-*)
+      add_cflags  "-miphoneos-version-min=${IOS_VERSION_MIN}"
+      add_ldflags "-miphoneos-version-min=${IOS_VERSION_MIN}"
+      iossim_sdk_dir="$(show_darwin_sdk_path iphonesimulator)"
+      if [ -d "${iossim_sdk_dir}" ]; then
+        add_cflags  "-isysroot ${iossim_sdk_dir}"
+        add_ldflags "-isysroot ${iossim_sdk_dir}"
+      fi
+      ;;
+  esac
+
+  # Handle Solaris variants. Solaris 10 needs -lposix4
+  case ${toolchain} in
+    sparc-solaris-*)
+      add_extralibs -lposix4
+      ;;
+    *-solaris-*)
+      add_extralibs -lposix4
+      ;;
+  esac
+
+  # Process ARM architecture variants
+  case ${toolchain} in
+    arm*)
+      # on arm, isa versions are supersets
+      case ${tgt_isa} in
+        arm64|armv8)
+          soft_enable neon
+          ;;
+        armv7|armv7s)
+          soft_enable neon
+          # Only enable neon_asm when neon is also enabled.
+          enabled neon && soft_enable neon_asm
+          # If someone tries to force it through, die.
+          if disabled neon && enabled neon_asm; then
+            die "Disabling neon while keeping neon-asm is not supported"
+          fi
+          case ${toolchain} in
+            # Apple iOS SDKs no longer support armv6 as of the version 9
+            # release (coincides with release of Xcode 7). Only enable media
+            # when using earlier SDK releases.
+            *-darwin*)
+              if [ "$(show_darwin_sdk_major_version iphoneos)" -lt 9 ]; then
+                soft_enable media
+              else
+                soft_disable media
+                RTCD_OPTIONS="${RTCD_OPTIONS}--disable-media "
+              fi
+              ;;
+            *)
+              soft_enable media
+              ;;
+          esac
+          ;;
+        armv6)
+          case ${toolchain} in
+            *-darwin*)
+              if [ "$(show_darwin_sdk_major_version iphoneos)" -lt 9 ]; then
+                soft_enable media
+              else
+                die "Your iOS SDK does not support armv6."
+              fi
+              ;;
+            *)
+              soft_enable media
+              ;;
+          esac
+          ;;
+      esac
+
+      asm_conversion_cmd="cat"
+
+      case ${tgt_cc} in
+        gcc)
+          link_with_cc=gcc
+          setup_gnu_toolchain
+          arch_int=${tgt_isa##armv}
+          arch_int=${arch_int%%te}
+          check_add_asflags --defsym ARCHITECTURE=${arch_int}
+          tune_cflags="-mtune="
+          if [ ${tgt_isa} = "armv7" ] || [ ${tgt_isa} = "armv7s" ]; then
+            if [ -z "${float_abi}" ]; then
+              check_cpp <<EOF && float_abi=hard || float_abi=softfp
+#ifndef __ARM_PCS_VFP
+#error "not hardfp"
+#endif
+EOF
+            fi
+            check_add_cflags  -march=armv7-a -mfloat-abi=${float_abi}
+            check_add_asflags -march=armv7-a -mfloat-abi=${float_abi}
+
+            if enabled neon || enabled neon_asm; then
+              check_add_cflags -mfpu=neon #-ftree-vectorize
+              check_add_asflags -mfpu=neon
+            fi
+          elif [ ${tgt_isa} = "arm64" ] || [ ${tgt_isa} = "armv8" ]; then
+            check_add_cflags -march=armv8-a
+            check_add_asflags -march=armv8-a
+          else
+            check_add_cflags -march=${tgt_isa}
+            check_add_asflags -march=${tgt_isa}
+          fi
+
+          enabled debug && add_asflags -g
+          asm_conversion_cmd="${source_path}/build/make/ads2gas.pl"
+          if enabled thumb; then
+            asm_conversion_cmd="$asm_conversion_cmd -thumb"
+            check_add_cflags -mthumb
+            check_add_asflags -mthumb -mimplicit-it=always
+          fi
+          ;;
+        vs*)
+          asm_conversion_cmd="${source_path}/build/make/ads2armasm_ms.pl"
+          AS_SFX=.s
+          msvs_arch_dir=arm-msvs
+          disable_feature multithread
+          disable_feature unit_tests
+          vs_version=${tgt_cc##vs}
+          # MSVC 2013 doesn't allow doing plain .exe projects for ARM,
+          # only "AppContainerApplication" which requires an AppxManifest.
+          # Therefore disable the examples, just build the library.
+          disable_feature examples
+          ;;
+        rvct)
+          CC=armcc
+          AR=armar
+          AS=armasm
+          LD="${source_path}/build/make/armlink_adapter.sh"
+          STRIP=arm-none-linux-gnueabi-strip
+          NM=arm-none-linux-gnueabi-nm
+          tune_cflags="--cpu="
+          tune_asflags="--cpu="
+          if [ -z "${tune_cpu}" ]; then
+            if [ ${tgt_isa} = "armv7" ]; then
+              if enabled neon || enabled neon_asm
+              then
+                check_add_cflags --fpu=softvfp+vfpv3
+                check_add_asflags --fpu=softvfp+vfpv3
+              fi
+              check_add_cflags --cpu=Cortex-A8
+              check_add_asflags --cpu=Cortex-A8
+            else
+              check_add_cflags --cpu=${tgt_isa##armv}
+              check_add_asflags --cpu=${tgt_isa##armv}
+            fi
+          fi
+          arch_int=${tgt_isa##armv}
+          arch_int=${arch_int%%te}
+          check_add_asflags --pd "\"ARCHITECTURE SETA ${arch_int}\""
+          enabled debug && add_asflags -g
+          add_cflags --gnu
+          add_cflags --enum_is_int
+          add_cflags --wchar32
+          ;;
+      esac
+
+      case ${tgt_os} in
+        none*)
+          disable_feature multithread
+          disable_feature os_support
+          ;;
+
+        android*)
+          if [ -z "${sdk_path}" ]; then
+            die "Must specify --sdk-path for Android builds."
+          fi
+
+          SDK_PATH=${sdk_path}
+          COMPILER_LOCATION=`find "${SDK_PATH}" \
+                             -name "arm-linux-androideabi-gcc*" -print -quit`
+          TOOLCHAIN_PATH=${COMPILER_LOCATION%/*}/arm-linux-androideabi-
+          CC=${TOOLCHAIN_PATH}gcc
+          CXX=${TOOLCHAIN_PATH}g++
+          AR=${TOOLCHAIN_PATH}ar
+          LD=${TOOLCHAIN_PATH}gcc
+          AS=${TOOLCHAIN_PATH}as
+          STRIP=${TOOLCHAIN_PATH}strip
+          NM=${TOOLCHAIN_PATH}nm
+
+          if [ -z "${alt_libc}" ]; then
+            alt_libc=`find "${SDK_PATH}" -name arch-arm -print | \
+              awk '{n = split($0,a,"/"); \
+                split(a[n-1],b,"-"); \
+                print $0 " " b[2]}' | \
+                sort -g -k 2 | \
+                awk '{ print $1 }' | tail -1`
+          fi
+
+          if [ -d "${alt_libc}" ]; then
+            add_cflags "--sysroot=${alt_libc}"
+            add_ldflags "--sysroot=${alt_libc}"
+          fi
+
+          # linker flag that routes around a CPU bug in some
+          # Cortex-A8 implementations (NDK Dev Guide)
+          add_ldflags "-Wl,--fix-cortex-a8"
+
+          enable_feature pic
+          soft_enable realtime_only
+          if [ ${tgt_isa} = "armv7" ]; then
+            soft_enable runtime_cpu_detect
+          fi
+          if enabled runtime_cpu_detect; then
+            add_cflags "-I${SDK_PATH}/sources/android/cpufeatures"
+          fi
+          ;;
+
+        darwin*)
+          XCRUN_FIND="xcrun --sdk iphoneos --find"
+          CXX="$(${XCRUN_FIND} clang++)"
+          CC="$(${XCRUN_FIND} clang)"
+          AR="$(${XCRUN_FIND} ar)"
+          AS="$(${XCRUN_FIND} as)"
+          STRIP="$(${XCRUN_FIND} strip)"
+          NM="$(${XCRUN_FIND} nm)"
+          RANLIB="$(${XCRUN_FIND} ranlib)"
+          AS_SFX=.s
+          LD="${CXX:-$(${XCRUN_FIND} ld)}"
+
+          # ASFLAGS is written here instead of using check_add_asflags
+          # because we need to overwrite all of ASFLAGS and purge the
+          # options that were put in above
+          ASFLAGS="-arch ${tgt_isa} -g"
+
+          add_cflags -arch ${tgt_isa}
+          add_ldflags -arch ${tgt_isa}
+
+          alt_libc="$(show_darwin_sdk_path iphoneos)"
+          if [ -d "${alt_libc}" ]; then
+            add_cflags -isysroot ${alt_libc}
+          fi
+
+          if [ "${LD}" = "${CXX}" ]; then
+            add_ldflags -miphoneos-version-min="${IOS_VERSION_MIN}"
+          else
+            add_ldflags -ios_version_min "${IOS_VERSION_MIN}"
+          fi
+
+          for d in lib usr/lib usr/lib/system; do
+            try_dir="${alt_libc}/${d}"
+            [ -d "${try_dir}" ] && add_ldflags -L"${try_dir}"
+          done
+
+          case ${tgt_isa} in
+            armv7|armv7s|armv8|arm64)
+              if enabled neon && ! check_xcode_minimum_version; then
+                soft_disable neon
+                log_echo "  neon disabled: upgrade Xcode (need v6.3+)."
+                if enabled neon_asm; then
+                  soft_disable neon_asm
+                  log_echo "  neon_asm disabled: upgrade Xcode (need v6.3+)."
+                fi
+              fi
+              ;;
+          esac
+
+          asm_conversion_cmd="${source_path}/build/make/ads2gas_apple.pl"
+
+          if [ "$(show_darwin_sdk_major_version iphoneos)" -gt 8 ]; then
+            check_add_cflags -fembed-bitcode
+            check_add_asflags -fembed-bitcode
+            check_add_ldflags -fembed-bitcode
+          fi
+          ;;
+
+        linux*)
+          enable_feature linux
+          if enabled rvct; then
+            # Check if we have CodeSourcery GCC in PATH. Needed for
+            # libraries
+            which arm-none-linux-gnueabi-gcc 2>&- || \
+              die "Couldn't find CodeSourcery GCC from PATH"
+
+            # Use armcc as a linker to enable translation of
+            # some gcc specific options such as -lm and -lpthread.
+            LD="armcc --translate_gcc"
+
+            # create configuration file (uses path to CodeSourcery GCC)
+            armcc --arm_linux_configure --arm_linux_config_file=arm_linux.cfg
+
+            add_cflags --arm_linux_paths --arm_linux_config_file=arm_linux.cfg
+            add_asflags --no_hide_all --apcs=/interwork
+            add_ldflags --arm_linux_paths --arm_linux_config_file=arm_linux.cfg
+            enabled pic && add_cflags --apcs=/fpic
+            enabled pic && add_asflags --apcs=/fpic
+            enabled shared && add_cflags --shared
+          fi
+          ;;
+      esac
+      ;;
+    mips*)
+      link_with_cc=gcc
+      setup_gnu_toolchain
+      tune_cflags="-mtune="
+      if enabled dspr2; then
+        check_add_cflags -mips32r2 -mdspr2
+      fi
+
+      if enabled runtime_cpu_detect; then
+        disable_feature runtime_cpu_detect
+      fi
+
+      if [ -n "${tune_cpu}" ]; then
+        case ${tune_cpu} in
+          p5600)
+            check_add_cflags -mips32r5 -mload-store-pairs
+            check_add_cflags -msched-weight -mhard-float -mfp64
+            check_add_asflags -mips32r5 -mhard-float -mfp64
+            check_add_ldflags -mfp64
+            ;;
+          i6400|p6600)
+            check_add_cflags -mips64r6 -mabi=64 -msched-weight
+            check_add_cflags  -mload-store-pairs -mhard-float -mfp64
+            check_add_asflags -mips64r6 -mabi=64 -mhard-float -mfp64
+            check_add_ldflags -mips64r6 -mabi=64 -mfp64
+            ;;
+        esac
+
+        if enabled msa; then
+          add_cflags -mmsa
+          add_asflags -mmsa
+          add_ldflags -mmsa
+        fi
+      fi
+
+      check_add_cflags -march=${tgt_isa}
+      check_add_asflags -march=${tgt_isa}
+      check_add_asflags -KPIC
+      ;;
+    x86*)
+      case  ${tgt_os} in
+        win*)
+          enabled gcc && add_cflags -fno-common
+          ;;
+        solaris*)
+          CC=${CC:-${CROSS}gcc}
+          CXX=${CXX:-${CROSS}g++}
+          LD=${LD:-${CROSS}gcc}
+          CROSS=${CROSS-g}
+          ;;
+        os2)
+          disable_feature pic
+          AS=${AS:-nasm}
+          add_ldflags -Zhigh-mem
+          ;;
+      esac
+
+      AS="${alt_as:-${AS:-auto}}"
+      case  ${tgt_cc} in
+        icc*)
+          CC=${CC:-icc}
+          LD=${LD:-icc}
+          setup_gnu_toolchain
+          add_cflags -use-msasm  # remove -use-msasm too?
+          # add -no-intel-extensions to suppress warning #10237
+          # refer to http://software.intel.com/en-us/forums/topic/280199
+          add_ldflags -i-static -no-intel-extensions
+          enabled x86_64 && add_cflags -ipo -static -O3 -no-prec-div
+          enabled x86_64 && AR=xiar
+          case ${tune_cpu} in
+            atom*)
+              tune_cflags="-x"
+              tune_cpu="SSE3_ATOM"
+              ;;
+            *)
+              tune_cflags="-march="
+              ;;
+          esac
+          ;;
+        gcc*)
+          link_with_cc=gcc
+          tune_cflags="-march="
+          setup_gnu_toolchain
+          #for 32 bit x86 builds, -O3 did not turn on this flag
+          enabled optimizations && disabled gprof && check_add_cflags -fomit-frame-pointer
+          ;;
+        vs*)
+          # When building with Microsoft Visual Studio the assembler is
+          # invoked directly. Checking at configure time is unnecessary.
+          # Skip the check by setting AS arbitrarily
+          AS=msvs
+          msvs_arch_dir=x86-msvs
+          vc_version=${tgt_cc##vs}
+          ;;
+      esac
+
+      bits=32
+      enabled x86_64 && bits=64
+      check_cpp <<EOF && bits=x32
+#if !defined(__ILP32__) || !defined(__x86_64__)
+#error "not x32"
+#endif
+EOF
+      case ${tgt_cc} in
+        gcc*)
+          add_cflags -m${bits}
+          add_ldflags -m${bits}
+          ;;
+      esac
+
+      soft_enable runtime_cpu_detect
+      # We can't use 'check_cflags' until the compiler is configured and CC is
+      # populated.
+      for ext in ${ARCH_EXT_LIST_X86}; do
+        # disable higher order extensions to simplify asm dependencies
+        if [ "$disable_exts" = "yes" ]; then
+          if ! disabled $ext; then
+            RTCD_OPTIONS="${RTCD_OPTIONS}--disable-${ext} "
+            disable_feature $ext
+          fi
+        elif disabled $ext; then
+          disable_exts="yes"
+        else
+          # use the shortened version for the flag: sse4_1 -> sse4
+          check_gcc_machine_option ${ext%_*} $ext
+        fi
+      done
+
+      if enabled external_build; then
+        log_echo "  skipping assembler detection"
+      else
+        case "${AS}" in
+          auto|"")
+            which nasm >/dev/null 2>&1 && AS=nasm
+            which yasm >/dev/null 2>&1 && AS=yasm
+            if [ "${AS}" = nasm ] ; then
+              # Apple ships version 0.98 of nasm through at least Xcode 6. Revisit
+              # this check if they start shipping a compatible version.
+              apple=`nasm -v | grep "Apple"`
+              [ -n "${apple}" ] \
+                && echo "Unsupported version of nasm: ${apple}" \
+                && AS=""
+            fi
+            [ "${AS}" = auto ] || [ -z "${AS}" ] \
+              && die "Neither yasm nor nasm have been found." \
+                     "See the prerequisites section in the README for more info."
+            ;;
+        esac
+        log_echo "  using $AS"
+      fi
+      [ "${AS##*/}" = nasm ] && add_asflags -Ox
+      AS_SFX=.asm
+      case  ${tgt_os} in
+        win32)
+          add_asflags -f win32
+          enabled debug && add_asflags -g cv8
+          EXE_SFX=.exe
+          ;;
+        win64)
+          add_asflags -f x64
+          enabled debug && add_asflags -g cv8
+          EXE_SFX=.exe
+          ;;
+        linux*|solaris*|android*)
+          add_asflags -f elf${bits}
+          enabled debug && [ "${AS}" = yasm ] && add_asflags -g dwarf2
+          enabled debug && [ "${AS}" = nasm ] && add_asflags -g
+          [ "${AS##*/}" = nasm ] && check_asm_align
+          ;;
+        darwin*)
+          add_asflags -f macho${bits}
+          enabled x86 && darwin_arch="-arch i386" || darwin_arch="-arch x86_64"
+          add_cflags  ${darwin_arch}
+          add_ldflags ${darwin_arch}
+          # -mdynamic-no-pic is still a bit of voodoo -- it was required at
+          # one time, but does not seem to be now, and it breaks some of the
+          # code that still relies on inline assembly.
+          # enabled icc && ! enabled pic && add_cflags -fno-pic -mdynamic-no-pic
+          enabled icc && ! enabled pic && add_cflags -fno-pic
+          ;;
+        iphonesimulator)
+          add_asflags -f macho${bits}
+          enabled x86 && sim_arch="-arch i386" || sim_arch="-arch x86_64"
+          add_cflags  ${sim_arch}
+          add_ldflags ${sim_arch}
+
+          if [ "$(show_darwin_sdk_major_version iphonesimulator)" -gt 8 ]; then
+            # yasm v1.3.0 doesn't know what -fembed-bitcode means, so turning it
+            # on is pointless (unless building a C-only lib). Warn the user, but
+            # do nothing here.
+            log "Warning: Bitcode embed disabled for simulator targets."
+          fi
+          ;;
+        os2)
+          add_asflags -f aout
+          enabled debug && add_asflags -g
+          EXE_SFX=.exe
+          ;;
+        *)
+          log "Warning: Unknown os $tgt_os while setting up $AS flags"
+          ;;
+      esac
+      ;;
+    *-gcc|generic-gnu)
+      link_with_cc=gcc
+      enable_feature gcc
+      setup_gnu_toolchain
+      ;;
+  esac
+
+  # Try to enable CPU specific tuning
+  if [ -n "${tune_cpu}" ]; then
+    if [ -n "${tune_cflags}" ]; then
+      check_add_cflags ${tune_cflags}${tune_cpu} || \
+        die "Requested CPU '${tune_cpu}' not supported by compiler"
+    fi
+    if [ -n "${tune_asflags}" ]; then
+      check_add_asflags ${tune_asflags}${tune_cpu} || \
+        die "Requested CPU '${tune_cpu}' not supported by assembler"
+    fi
+    if [ -z "${tune_cflags}${tune_asflags}" ]; then
+      log_echo "Warning: CPU tuning not supported by this toolchain"
+    fi
+  fi
+
+  if enabled debug; then
+    check_add_cflags -g && check_add_ldflags -g
+  else
+    check_add_cflags -DNDEBUG
+  fi
+
+  enabled gprof && check_add_cflags -pg && check_add_ldflags -pg
+  enabled gcov &&
+    check_add_cflags -fprofile-arcs -ftest-coverage &&
+    check_add_ldflags -fprofile-arcs -ftest-coverage
+
+  if enabled optimizations; then
+    if enabled rvct; then
+      enabled small && check_add_cflags -Ospace || check_add_cflags -Otime
+    else
+      enabled small && check_add_cflags -O2 ||  check_add_cflags -O3
+    fi
+  fi
+
+  # Position Independent Code (PIC) support, for building relocatable
+  # shared objects
+  enabled gcc && enabled pic && check_add_cflags -fPIC
+
+  # Work around longjmp interception on glibc >= 2.11, to improve binary
+  # compatibility. See http://code.google.com/p/webm/issues/detail?id=166
+  enabled linux && check_add_cflags -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
+
+  # Check for strip utility variant
+  ${STRIP} -V 2>/dev/null | grep GNU >/dev/null && enable_feature gnu_strip
+
+  # Try to determine target endianness
+  check_cc <<EOF
+unsigned int e = 'O'<<24 | '2'<<16 | 'B'<<8 | 'E';
+EOF
+    [ -f "${TMP_O}" ] && od -A n -t x1 "${TMP_O}" | tr -d '\n' |
+        grep '4f *32 *42 *45' >/dev/null 2>&1 && enable_feature big_endian
+
+    # Try to find which inline keywords are supported
+    check_cc <<EOF && INLINE="inline"
+static inline function() {}
+EOF
+
+  # Almost every platform uses pthreads.
+  if enabled multithread; then
+    case ${toolchain} in
+      *-win*-vs*)
+        ;;
+      *-android-gcc)
+        ;;
+      *)
+        check_header pthread.h && add_extralibs -lpthread
+        ;;
+    esac
+  fi
+
+  # only for MIPS platforms
+  case ${toolchain} in
+    mips*)
+      if enabled big_endian; then
+        if enabled dspr2; then
+          echo "dspr2 optimizations are available only for little endian platforms"
+          disable_feature dspr2
+        fi
+        if enabled msa; then
+          echo "msa optimizations are available only for little endian platforms"
+          disable_feature msa
+        fi
+      fi
+      ;;
+  esac
+
+  # glibc needs these
+  if enabled linux || [ "$toolchain" = "generic-gnu" ]; then
+    add_cflags -D_LARGEFILE_SOURCE
+    add_cflags -D_FILE_OFFSET_BITS=64
+  fi
+}
+
+process_toolchain() {
+  process_common_toolchain
+}
+
+print_config_mk() {
+  saved_prefix="${prefix}"
+  prefix=$1
+  makefile=$2
+  shift 2
+  for cfg; do
+    if enabled $cfg; then
+      upname="`toupper $cfg`"
+      echo "${prefix}_${upname}=yes" >> $makefile
+    fi
+  done
+  prefix="${saved_prefix}"
+}
+
+print_config_h() {
+  saved_prefix="${prefix}"
+  prefix=$1
+  header=$2
+  shift 2
+  for cfg; do
+    upname="`toupper $cfg`"
+    if enabled $cfg; then
+      echo "#define ${prefix}_${upname} 1" >> $header
+    else
+      echo "#define ${prefix}_${upname} 0" >> $header
+    fi
+  done
+  prefix="${saved_prefix}"
+}
+
+print_config_vars_h() {
+  header=$1
+  shift
+  while [ $# -gt 0 ]; do
+    upname="`toupper $1`"
+    echo "#define ${upname} $2" >> $header
+    shift 2
+  done
+}
+
+print_webm_license() {
+  saved_prefix="${prefix}"
+  destination=$1
+  prefix="$2"
+  suffix="$3"
+  shift 3
+  cat <<EOF > ${destination}
+${prefix} Copyright (c) 2016, Alliance for Open Media. All rights reserved.${suffix}
+${prefix} ${suffix}
+${prefix} This source code is subject to the terms of the BSD 2 Clause License and${suffix}
+${prefix} the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License${suffix}
+${prefix} was not distributed with this source code in the LICENSE file, you can${suffix}
+${prefix} obtain it at www.aomedia.org/license/software. If the Alliance for Open${suffix}
+${prefix} Media Patent License 1.0 was not distributed with this source code in the${suffix}
+${prefix} PATENTS file, you can obtain it at www.aomedia.org/license/patent.${suffix}
+EOF
+  prefix="${saved_prefix}"
+}
+
+process_targets() {
+  true;
+}
+
+process_detect() {
+  true;
+}
+
+enable_feature logging
+logfile="config.log"
+self=$0
+process() {
+  cmdline_args="$@"
+  process_cmdline "$@"
+  if enabled child; then
+    echo "# ${self} $@" >> ${logfile}
+  else
+    echo "# ${self} $@" > ${logfile}
+  fi
+  post_process_common_cmdline
+  post_process_cmdline
+  process_toolchain
+  process_detect
+  process_targets
+
+  OOT_INSTALLS="${OOT_INSTALLS}"
+  if enabled source_path_used; then
+  # Prepare the PWD for building.
+  for f in ${OOT_INSTALLS}; do
+    install -D "${source_path}/$f" "$f"
+  done
+  fi
+  cp "${source_path}/build/make/Makefile" .
+
+  clean_temp_files
+  true
+}