diff --git a/src/modules/Makefile b/src/modules/Makefile
index 1a52d65b..3cd51023 100644
--- a/src/modules/Makefile
+++ b/src/modules/Makefile
@@ -4,10 +4,10 @@ uname_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
 
 # Compile flags for linux / osx
 ifeq ($(uname_S),Linux)
-	SHOBJ_CFLAGS ?=  -fno-common -g -ggdb
+	SHOBJ_CFLAGS ?=  -fno-common -g -ggdb -std=c99
 	SHOBJ_LDFLAGS ?= -shared
 else
-	SHOBJ_CFLAGS ?= -dynamic -fno-common -g -ggdb
+	SHOBJ_CFLAGS ?= -dynamic -fno-common -g -ggdb -std=c99
 	SHOBJ_LDFLAGS ?= -bundle -undefined dynamic_lookup
 endif