Frameworks/base: Ignore unknown pragmas in core/jni

Preparation for a switch to Clang.

Change-Id: Iabe1d79474a617bec66dd4bf58002b1a372f6d23
diff --git a/core/jni/Android.mk b/core/jni/Android.mk
index adeffad..d53a5b80 100644
--- a/core/jni/Android.mk
+++ b/core/jni/Android.mk
@@ -261,7 +261,9 @@
 
 LOCAL_MODULE:= libandroid_runtime
 
-LOCAL_CFLAGS += -Wall -Werror -Wunused -Wunreachable-code
+# -Wno-unknown-pragmas: necessary for Clang as the GL bindings need to turn
+#                       off a GCC warning that Clang doesn't know.
+LOCAL_CFLAGS += -Wall -Werror -Wunused -Wunreachable-code -Wno-unknown-pragmas
 
 include $(BUILD_SHARED_LIBRARY)