diff --git a/src/pkg/runtime/malloc.c b/src/pkg/runtime/malloc.c
index d56d0dcf31..1e133168b1 100644
--- a/src/pkg/runtime/malloc.c
+++ b/src/pkg/runtime/malloc.c
@@ -21,7 +21,7 @@ MHeap runtime·mheap;
 #pragma dataflag NOPTR
 MStats runtime·memstats;
 
-void runtime·cmallocgc(uintptr size, Type *typ, uint32 flag, void **ret);
+void runtime·cmallocgc(uintptr size, Type *typ, intgo flag, void **ret);
 
 void*
 runtime·mallocgc(uintptr size, Type *typ, uint32 flag)