libvpx: Pull from upstream

source/libvpx/build/make/configure.sh

 #!/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 libvpx
 ##  related.
 ##
 ##  This build system is based in part on the FFmpeg configure script.
 ##
@@ skipping 718 matching lines @@
 
     # 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).
+    IOS_VERSION_MIN="6.0"
+
     # Handle darwin variants. Newer SDKs allow targeting older
     # platforms, so find the newest SDK available.
     case ${toolchain} in
         *-darwin*)
             if [ -z "${DEVELOPER_DIR}" ]; then
                 DEVELOPER_DIR=`xcode-select -print-path 2> /dev/null`
                 [ $? -ne 0 ] && OSX_SKIP_DIR_CHECK=1
             fi
             if [ -z "${OSX_SKIP_DIR_CHECK}" ]; then
                 OSX_SDK_ROOTS="${DEVELOPER_DIR}/SDKs"
@@ skipping 32 matching lines @@
             ;;
         *-darwin12-*)
             add_cflags  "-mmacosx-version-min=10.8"
             add_ldflags "-mmacosx-version-min=10.8"
             ;;
         *-darwin13-*)
             add_cflags  "-mmacosx-version-min=10.9"
             add_ldflags "-mmacosx-version-min=10.9"
             ;;
         *-iphonesimulator-*)
-            add_cflags  "-miphoneos-version-min=5.0"
-            add_ldflags "-miphoneos-version-min=5.0"
+            add_cflags  "-miphoneos-version-min=${IOS_VERSION_MIN}"
+            add_ldflags "-miphoneos-version-min=${IOS_VERSION_MIN}"
             osx_sdk_dir="$(xcrun --sdk iphonesimulator --show-sdk-path)"
             add_cflags  "-isysroot ${osx_sdk_dir}"
             add_ldflags "-isysroot ${osx_sdk_dir}"
             ;;
     esac
 
     # Handle Solaris variants. Solaris 10 needs -lposix4
     case ${toolchain} in
         sparc-solaris-*)
             add_extralibs -lposix4
@@ skipping 160 matching lines @@
             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)"
-            LD="$(${XCRUN_FIND} ld)"
             AS="$(${XCRUN_FIND} as)"
             STRIP="$(${XCRUN_FIND} strip)"
             NM="$(${XCRUN_FIND} nm)"
             RANLIB="$(${XCRUN_FIND} ranlib)"
             AS_SFX=.s
 
+            # Special handling of ld for armv6 because libclang_rt.ios.a does
+            # not contain armv6 support in Apple's clang package:
+            #   Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn).
+            # TODO(tomfinegan): Remove this. Our minimum iOS version (6.0)
+            # renders support for armv6 unnecessary because the 3GS and up
+            # support neon.
+            if [ "${tgt_isa}" = "armv6" ]; then
+                LD="$(${XCRUN_FIND} ld)"
+            else
+                LD="${CXX:-$(${XCRUN_FIND} ld)}"
+            fi
+
             # 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"
 
             alt_libc="$(xcrun --sdk iphoneos --show-sdk-path)"
             add_cflags -arch ${tgt_isa} -isysroot ${alt_libc}
-            add_ldflags -arch ${tgt_isa} -ios_version_min 7.0
+            add_ldflags -arch ${tgt_isa}
+
+            if [ "${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
 
             asm_conversion_cmd="${source_path}/build/make/ads2gas_apple.pl"
          ;;
 
         linux*)
@@ skipping 401 matching lines @@
     # 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
 }