diff --git a/winsup/cygwin/miscfuncs.cc b/winsup/cygwin/miscfuncs.cc
index deb648eff..b4ab7cd7d 100644
--- a/winsup/cygwin/miscfuncs.cc
+++ b/winsup/cygwin/miscfuncs.cc
@@ -16,6 +16,7 @@ details. */
 #include "fhandler.h"
 #include "exception.h"
 #include "tls_pbuf.h"
+#include "mmap_alloc.h"
 
 int __reg2
 check_invalid_virtual_addr (const void *s, unsigned sz)