diff --git a/makefile b/makefile
index 49f7761..9cb0779 100644
--- a/makefile
+++ b/makefile
@@ -1,8 +1,8 @@
 sequential: src/sequential.c src/util.c src/kmp.c build
-	gcc src/kmp.c src/util.c src/sequential.c -o build/kmp-s.out
+	gcc -std=c99 src/kmp.c src/util.c src/sequential.c -o build/kmp-s.out
 
 sequential-time: src/sequential.c src/util.c src/kmp.c build
-	gcc -D TIME src/kmp.c src/util.c src/sequential.c -o build/kmp-st.out
+	gcc -std=c99 -D TIME src/kmp.c src/util.c src/sequential.c -o build/kmp-st.out
 
 parallel: src/parallel.c src/util.c src/kmp.c build
 	mpicc -std=c99 src/parallel.c src/util.c src/kmp.c -lm -o build/kmp-p.out