--- a/tmclock.c
+++ b/tmclock.c
@@ -18,8 +18,10 @@
 #include <sys/time.h>
 #else
 #include <time.h>
+#ifdef timezone
 extern long	timezone;	/* should be in <time.h>, but isn't on Sun */
 #endif
+#endif
 
 long	tzone;