diff --git a/Makefile b/Makefile
index 85f836b..b0d2936 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 CC = gcc
-CFLAGS = -O0 -g3 -Wall
+CFLAGS = -O0 -g3 -Wall -std=c99
 LFLAGS = 
 DEPS = protobuf.h
 OBJS = protobuf.o varint.o
@@ -21,4 +21,4 @@ clean:
 	rm -f protobuf_reader;
 	cd test; make clean;
 	
-rebuild: clean all
\ No newline at end of file
+rebuild: clean all
diff --git a/test/Makefile b/test/Makefile
index 7a17da4..ae5963e 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,5 +1,5 @@
 CC = gcc
-CFLAGS = -O0 -g3 -Wall -I../
+CFLAGS = -O0 -g3 -Wall -I../ -std=c99
 LFLAGS = 
 DEPS = ../protobuf.h
 OBJS = testit.o ../protobuf.o ../varint.o Test1_protobuf.o Test2_protobuf.o Test3_protobuf.o
@@ -16,4 +16,4 @@ clean:
 	rm -f *.o
 	rm -f test_protobuf
 	
-rebuild: clean all
\ No newline at end of file
+rebuild: clean all