path: don't access global option struct

The path functions need to access the option that forces non-default
config directories. Just add it as a field to mpv_global - it seems
justified. The accessed options were always enforced as immutable after
init, so there's not much of a change.

common/global.h

@@ -8,6 +8,7 @@ struct mpv_global {
     struct mp_log *log;
     struct m_config_shadow *config;
     struct mp_client_api *client_api;
+    char *configdir;
 
     // Using this is deprecated and should be avoided (missing synchronization).
     // Use m_config_cache to access mpv_global.config instead.

options/path.c

@@ -61,6 +61,19 @@ static const char *const config_dirs[] = {
     "global",
 };
 
+void mp_init_paths(struct mpv_global *global, struct MPOpts *opts)
+{
+    TA_FREEP(&global->configdir);
+
+    const char *force_configdir = getenv("MPV_HOME");
+    if (opts->force_configdir && opts->force_configdir[0])
+        force_configdir = opts->force_configdir;
+    if (!opts->load_config)
+        force_configdir = "";
+
+    global->configdir = talloc_strdup(global, force_configdir);
+}
+
 // Return a platform specific path using a path type as defined in osdep/path.h.
 // Keep in mind that the only way to free the return value is freeing talloc_ctx
 // (or its children), as this function can return a statically allocated string.
@@ -70,15 +83,10 @@ static const char *mp_get_platform_path(void *talloc_ctx,
 {
     assert(talloc_ctx);
 
-    const char *force_configdir = getenv("MPV_HOME");
-    if (global->opts->force_configdir && global->opts->force_configdir[0])
-        force_configdir = global->opts->force_configdir;
-    if (!global->opts->load_config)
-        force_configdir = "";
-    if (force_configdir) {
+    if (global->configdir) {
         for (int n = 0; n < MP_ARRAY_SIZE(config_dirs); n++) {
             if (strcmp(config_dirs[n], type) == 0)
-                return (n == 0 && force_configdir[0]) ? force_configdir : NULL;
+                return (n == 0 && global->configdir[0]) ? global->configdir : NULL;
         }
     }
 

options/path.h

@@ -24,6 +24,9 @@
 #include "misc/bstr.h"
 
 struct mpv_global;
+struct MPOpts;
+
+void mp_init_paths(struct mpv_global *global, struct MPOpts *opts);
 
 // Search for the input filename in several paths. These include user and global
 // config locations by default. Some platforms may implement additional platform

player/main.c

@@ -338,6 +338,7 @@ int mp_initialize(struct MPContext *mpctx, char **options)
     if (options)
         m_config_preparse_command_line(mpctx->mconfig, mpctx->global, options);
 
+    mp_init_paths(mpctx->global, opts);
     mp_update_logging(mpctx, true);
 
     if (options) {