libvpx: Pull from upstream

source/libvpx/build/make/configure.sh

Index: source/libvpx/build/make/configure.sh
===================================================================
--- source/libvpx/build/make/configure.sh	(revision 292608)
+++ source/libvpx/build/make/configure.sh	(working copy)
@@ -736,6 +736,9 @@
     # 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 ${toolchain} in
@@ -788,8 +791,8 @@
             add_ldflags "-mmacosx-version-min=10.9"
             ;;
         *-iphonesimulator-*)
-            add_cflags  "-miphoneos-version-min=5.0"
-            add_ldflags "-miphoneos-version-min=5.0"
+            add_cflags  "-miphoneos-version-min=${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}"
@@ -970,12 +973,10 @@
           ;;
 
         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)"
@@ -982,6 +983,18 @@
             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
@@ -989,8 +1002,14 @@
 
             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}"