Fix -fno-common

Index: src/common.c
--- src/common.c.orig
+++ src/common.c
@@ -14,6 +14,10 @@
 #include "common.h"
 #include "document.h"
 
+struct timespec pauselength;
+struct timespec pauseleft;
+HighScores hs;
+
 /* Creates empty board windows. Needs to be called once at the
  * beginning of each game */
 int 
