Add LOCAL_NO_LIBGCC.

This can be used to compile independent libraries without the need for
libgcc.a.

Change-Id: I924200995569d9a978ddbaa6ec321d80734f1374
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index f30c8ba..bd6902c 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -142,6 +142,7 @@
 LOCAL_PROTOC_FLAGS:=
 LOCAL_PROTO_JAVA_OUTPUT_PARAMS:=
 LOCAL_NO_CRT:=
+LOCAL_NO_LIBGCC:=
 LOCAL_PROPRIETARY_MODULE:=
 LOCAL_OEM_MODULE:=
 LOCAL_ODM_MODULE:=