diff --git a/msdos/dosmem.c b/msdos/dosmem.c
index 5339d10d01f..6506fa1ace3 100644
--- a/msdos/dosmem.c
+++ b/msdos/dosmem.c
@@ -10,6 +10,7 @@
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
 #ifdef HAVE_SYS_MMAN_H
 # include <sys/mman.h>
 #endif