Fix gcc test issues.

Change-Id: I2b26b779f5198c7c9362a452b971260a8852aa7b
diff --git a/libc/malloc_debug/Android.mk b/libc/malloc_debug/Android.mk
index 4c2c7f3..3eb0790 100644
--- a/libc/malloc_debug/Android.mk
+++ b/libc/malloc_debug/Android.mk
@@ -72,5 +72,6 @@
 LOCAL_CFLAGS := \
     -Wall \
     -Werror \
+    -Wno-error=format-zero-length \
 
 include $(BUILD_NATIVE_TEST)