Make gnu++11 the default standard version.

There are a _lot_ of users of `typeof` in the tree, and they'll need a
GNU flavored standard. Rather than fixing up all of these
individually, let's just use gnu++11 as the default.

Bug: 18466763
Change-Id: Ia1bd3adaa74fadba259fda3d37653fb8d5cff69a
diff --git a/core/config.mk b/core/config.mk
index aa82e93..c9453ef 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -117,7 +117,7 @@
 COMMON_GLOBAL_CFLAGS:= -DANDROID -fmessage-length=0 -W -Wall -Wno-unused -Winit-self -Wpointer-arith
 COMMON_RELEASE_CFLAGS:= -DNDEBUG -UDEBUG
 
-COMMON_GLOBAL_CPPFLAGS:= $(COMMON_GLOBAL_CFLAGS) -Wsign-promo
+COMMON_GLOBAL_CPPFLAGS:= $(COMMON_GLOBAL_CFLAGS) -Wsign-promo -std=gnu++11
 COMMON_RELEASE_CPPFLAGS:= $(COMMON_RELEASE_CFLAGS)
 
 # Set the extensions used for various packages