diff --git a/vlib/builtin/cfns.v b/vlib/builtin/cfns.v
index 1e5654c544..3a0171200d 100644
--- a/vlib/builtin/cfns.v
+++ b/vlib/builtin/cfns.v
@@ -3,7 +3,7 @@ module builtin
 
 // <string.h>
 fn C.memcpy(byteptr, byteptr, int) voidptr
-fn C.memmove(byteptr, byteptr, int)
+fn C.memmove(byteptr, byteptr, int) voidptr
 
 //fn C.malloc(int) byteptr
 fn C.realloc(a byteptr, b int) byteptr
diff --git a/vlib/compiler/cheaders.v b/vlib/compiler/cheaders.v
index b9b4c44248..2038e6ef7e 100644
--- a/vlib/compiler/cheaders.v
+++ b/vlib/compiler/cheaders.v
@@ -9,7 +9,7 @@ CommonCHeaders = '
 #include <signal.h>
 #include <stdarg.h> // for va_list
 #include <inttypes.h>  // int64_t etc
-//#include <string.h> // memcpy
+#include <string.h> // memcpy
 
 #ifndef _WIN32
 #include <ctype.h>