Fix RS_TRIPLE and RS_TRIPLE_CFLAGS.

Bug: 17333374

Add RS_TRIPLE_CFLAGS to ensure that we build with the proper defines on
targets like x86. This also changes all build targets to use the
proper 32/64-bit triples when creating their runtime libraries.

Change-Id: I8f6175b1a14af6d03ee90f32069f3688ec227fb9
diff --git a/core/clang/TARGET_arm64.mk b/core/clang/TARGET_arm64.mk
index 98bbeb2..0264321 100644
--- a/core/clang/TARGET_arm64.mk
+++ b/core/clang/TARGET_arm64.mk
@@ -51,3 +51,4 @@
   $(CLANG_CONFIG_arm64_TARGET_EXTRA_LDFLAGS)
 
 RS_TRIPLE := aarch64-linux-android
+RS_TRIPLE_CFLAGS :=