--- a/x3270/xscreen.h_old	2021-08-03 15:23:42.725100426 +0800
+++ b/x3270/xscreen.h	2021-08-03 15:23:54.081295953 +0800
@@ -163,5 +163,5 @@
     struct font_list	*next;
     char		*mlabel;
 };
-struct font_list *font_list;
-int font_count;
+extern struct font_list *font_list;
+extern int font_count;
--- a/include/glue.h	2021-08-03 15:43:01.289032463 +0800
+++ b/include/glue.h	2021-08-03 15:41:24.155363894 +0800
@@ -49,5 +49,5 @@
 void register_merge_profile(merge_profile_t *);
 
 /* XtGlue.c */
-void (*Error_redirect)(const char *);
-void (*Warning_redirect)(const char *);
+extern void (*Error_redirect)(const char *);
+extern void (*Warning_redirect)(const char *);