Add x86-iphonesimulator-gcc target.

macho32 i386 with:
- -miphoneos-version-min=5.0
- -isysroot from xcrun --sdk iphonesimulator

Change-Id: I6bb43eebab39a71cdb76264644eba14c22d736c2
diff --git a/configure b/configure
index b6d645a..5fd5a90 100755
--- a/configure
+++ b/configure
@@ -120,6 +120,7 @@
 all_platforms="${all_platforms} x86-darwin11-gcc"
 all_platforms="${all_platforms} x86-darwin12-gcc"
 all_platforms="${all_platforms} x86-darwin13-gcc"
+all_platforms="${all_platforms} x86-iphonesimulator-gcc"
 all_platforms="${all_platforms} x86-linux-gcc"
 all_platforms="${all_platforms} x86-linux-icc"
 all_platforms="${all_platforms} x86-os2-gcc"
@@ -723,6 +724,10 @@
             # iOS/ARM builds do not work with gtest. This does not match
             # x86 targets.
         ;;
+        *-iphonesimulator-*)
+            soft_enable webm_io
+            soft_enable libyuv
+        ;;
         *-win*)
             # Some mingw toolchains don't have pthread available by default.
             # Treat these more like visual studio where threading in gtest