Fix -fno-common

Index: src/cpat.h
--- src/cpat.h.orig
+++ src/cpat.h
@@ -224,10 +224,10 @@ typedef struct {
     bool available;
 } HighScores;
     
-struct timespec pauselength;
-struct timespec pauseleft;
+extern struct timespec pauselength;
+extern struct timespec pauseleft;
 
-HighScores hs;
+extern HighScores hs;
 
 /* This is the background color of the boards */
 static chtype boardbkgd = ' ' | COLOR_PAIR(BKGD_COLOR);
