diff --git a/rebar.config b/rebar.config
index 20a0778..5cf51a1 100644
--- a/rebar.config
+++ b/rebar.config
@@ -10,6 +10,6 @@
              ]}.
 
 {port_env, [
-            {"CC", "c99"},
-            {"CFLAGS", "$CFLAGS -Wall -Werror -O3"}
+            {"CC", "cc"},
+            {"CFLAGS", "$CFLAGS -std=c99 -Wall -Werror -O3"}
            ]}.