Fix Darwin build caused by -Wunused-parameter.

bug 16172793

Change-Id: I1d0514c00085cb5d18ebdd064e96885d6eaa1e59
diff --git a/libutils/Android.mk b/libutils/Android.mk
index 6164c10..2d77ef2 100644
--- a/libutils/Android.mk
+++ b/libutils/Android.mk
@@ -66,6 +66,9 @@
 ifeq ($(HOST_OS), linux)
 LOCAL_SRC_FILES += Looper.cpp
 endif
+ifeq ($(HOST_OS),darwin)
+LOCAL_CFLAGS += -Wno-unused-parameter
+endif
 LOCAL_MODULE:= libutils
 LOCAL_STATIC_LIBRARIES := liblog
 LOCAL_CFLAGS += $(host_commonCflags)