Add options for building/testing with coverage.

    acov --clean
    mm -B NATIVE_COVERAGE=true ART_COVERAGE=true test-art-host
    acov --host

-B is needed because you need to be sure you rebuild *all* of ART with
coverage.

Change-Id: Ib94ef610bd1b44dc45624877710ed733051b7a50
diff --git a/build/Android.common_build.mk b/build/Android.common_build.mk
index ad4c987..3000cdf 100644
--- a/build/Android.common_build.mk
+++ b/build/Android.common_build.mk
@@ -238,10 +238,14 @@
 
 ifeq ($(HOST_OS),linux)
   # Larger frame-size for host clang builds today
-  ifndef SANITIZE_HOST
-    art_host_non_debug_cflags += -Wframe-larger-than=2700
+  ifneq ($(ART_COVERAGE),true)
+    ifneq ($(NATIVE_COVERAGE),true)
+      ifndef SANITIZE_HOST
+        art_host_non_debug_cflags += -Wframe-larger-than=2700
+      endif
+      art_target_non_debug_cflags += -Wframe-larger-than=1728
+    endif
   endif
-  art_target_non_debug_cflags += -Wframe-larger-than=1728
 endif
 
 ifndef LIBART_IMG_HOST_BASE_ADDRESS