path: expose platform-specific path resolvers

DOCS/man/mpv.rst

@@ -330,7 +330,16 @@ additionally wrapped in the fixed-length syntax, e.g. ``%n%string_of_length_n``
 Some mpv options interpret paths starting with ``~``. Currently, the prefix
 ``~~/`` expands to the mpv configuration directory (usually ``~/.config/mpv/``).
 ``~/`` expands to the user's home directory. (The trailing ``/`` is always
-required.)
+required.) There are the following paths as well:
+
+=============== ================================================================
+Name            Meaning
+=============== ================================================================
+``~home/``      same as ``~~/``
+``~global/``    the global config path, if available
+``~osxbundle/`` the OSX bundle resource path (OSX only)
+=============== ================================================================
+
 
 Per-File Options
 ----------------

options/path.c

@@ -182,6 +182,11 @@ char *mp_get_user_path(void *talloc_ctx, struct mpv_global *global,
                 res = mp_find_config_file(talloc_ctx, global, rest0);
             } else if (bstr_equals0(prefix, "")) {
                 res = mp_path_join(talloc_ctx, bstr0(getenv("HOME")), rest);
+            } else {
+                char type[80];
+                snprintf(type, sizeof(type), "%.*s", BSTR_P(prefix));
+                res = talloc_strdup(talloc_ctx,
+                                    mp_get_platform_path(talloc_ctx, type));
             }
         }
     }