Include sys/types.h before system.h.

diff --git a/src/tsort.c b/src/tsort.c
index be0be95..1052ffb 100644 (file)
--- a/src/tsort.c
+++ b/src/tsort.c
@@ -26,6 +26,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <getopt.h>
+#include <sys/types.h>
 
 #include "system.h"
 #include "closeout.h"