diff --git a/src/module_support.c b/src/module_support.c
index d5d77a685bb25922ed9f529967092a958d55b741..8f3cbcfb5c706c750da9a48713f2fb0e833d0822 100644
--- a/src/module_support.c
+++ b/src/module_support.c
@@ -3,6 +3,7 @@
 #include "interpret.h"
 #include "svalue.h"
 #include "stralloc.h"
+#include "pike_types.h"
 
 enum error_type {
   ERR_NONE,