Use -Werror in frameworks/native/cmds/cmd

* Ignore return value of getfilecon?

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Ic7d67907a1cf0ba415aa0753bbd55bde06c8dd06
Merged-In: I341e6047dbb5b49a92f69df74b073d2f54a7754d
diff --git a/cmds/cmd/Android.mk b/cmds/cmd/Android.mk
index d565e57..4868555 100644
--- a/cmds/cmd/Android.mk
+++ b/cmds/cmd/Android.mk
@@ -10,6 +10,8 @@
     libselinux \
 	libbinder
 
+LOCAL_CFLAGS := -Wall -Werror
+
 LOCAL_C_INCLUDES += \
     $(JNI_H_INCLUDE)