Cherrypick "Don't include TargetConditionals.h when building for android."

> Move the include of the Mac TargetConditionals.h file to after we've
> checked if we're building for Android. Apparently this file doesn't
> exist on all macs used to build android and the rest of android builds
> fine without it, so including it there causes the build to fail. It
> appears to only be used to test TARGET_OS_IPHONE which will never be
> true on android.
> BUG=
> Review URL:
> Cr-Commit-Position: refs/heads/master@{#293495}

Bug: 17401514
(cherry picked from commit 8001123e38cc0174b9ab616e684f7b788da87f2c)

Change-Id: I159d749f96b9564c4173c04d6ee572d2d23d1c90
diff --git a/build/build_config.h b/build/build_config.h
index b48db72..5534846 100644
--- a/build/build_config.h
+++ b/build/build_config.h
@@ -14,10 +14,6 @@
-#if defined(__APPLE__)
-#include <TargetConditionals.h>
 // A set of macros to use for platform detection.
 #if defined(__native_client__)
 // __native_client__ must be first, so that other OS_ defines are not set.
@@ -25,6 +21,10 @@
 #elif defined(ANDROID)
 #define OS_ANDROID 1
 #elif defined(__APPLE__)
+// only include TargetConditions after testing ANDROID as some android builds
+// on mac don't have this header available and it's not needed unless the target
+// is really mac/ios.
+#include <TargetConditionals.h>
 #define OS_MACOSX 1
 #define OS_IOS 1