diff --git a/osx.m b/osx.m
index fdcef1e..53d14ba 100644
--- a/osx.m
+++ b/osx.m
@@ -80,6 +80,7 @@
 #define COMBINED /* we put all the puzzles in one binary in this port */
 
 #include <ctype.h>
+#include <time.h>
 #include <sys/time.h>
 #import <Cocoa/Cocoa.h>
 #include "puzzles.h"