Ensure all tools are building with -Wall and -Werror

Added -Werror to CFLAGS.

Change-Id: Ib1459098ac008ca4064d186cdbe20be13aa08d61
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/Makefile b/Makefile
index 110d284..23feac9 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@
 
 INSTALLED_EXE += $(EXE)
 
-CFLAGS += -Wall -Wno-unused-result
+CFLAGS += -Wall -Werror -Wno-unused-result
 
 INC_FLAG += $(shell pkg-config --cflags --libs libsystemd) -I. -O2
 LIB_FLAG += $(shell pkg-config  --libs libsystemd)