diff -urN angband-4.1.3.orig/src/mon-blows.h angband-4.1.3/src/mon-blows.h
--- angband-4.1.3.orig/src/mon-blows.h	2018-07-21 23:49:08.000000000 -0500
+++ angband-4.1.3/src/mon-blows.h	2022-01-02 12:04:52.000000000 -0600
@@ -35,7 +35,7 @@
 	struct blow_method *next;
 };
 
-struct blow_method *blow_methods;
+extern struct blow_method *blow_methods;
 
 /**
  * Storage for context information for effect handlers called in
@@ -76,7 +76,7 @@
 	struct blow_effect *next;
 };
 
-struct blow_effect *blow_effects;
+extern struct blow_effect *blow_effects;
 
 /* Functions */
 int blow_index(const char *name);