config: move some settings to a global config

src/include/86box/86box.h

@@ -175,6 +175,7 @@ extern int    hook_enabled;                 /* (C) Keyboard hook is enabled */
 extern char exe_path[2048];     /* path (dir) of executable */
 extern char usr_path[1024];     /* path (dir) of user data */
 extern char cfg_path[1024];     /* full path of config file */
+extern char global_cfg_path[1024]; /* full path of global config file */
 extern int  open_dir_usr_path;  /* default file open dialog directory of usr_path */
 extern char uuid[MAX_UUID_LEN]; /* UUID or machine identifier */
 #ifndef USE_NEW_DYNAREC