diff --git a/include/wine/port.h b/include/wine/port.h
index 5f98c6c84e7..0cf862889e2 100644
--- a/include/wine/port.h
+++ b/include/wine/port.h
@@ -283,6 +283,7 @@ extern int getopt_long_only (int ___argc, char *const *___argv,
 #endif  /* HAVE_GETOPT_LONG */
 
 #ifndef HAVE_FUTIMES
+struct timeval;
 int futimes(int fd, const struct timeval tv[2]);
 #endif