fix mpv global config dir

confdir.patch

@@ -0,0 +1,13 @@
+diff --git a/meson.build b/meson.build
+index 4aada48731..39a37853de 100644
+--- a/meson.build
++++ b/meson.build
+@@ -1655,7 +1655,7 @@ sys.stdout.write(features)
+ '''
+ feature_str = run_command(python, '-c', feature_sort, feature_keys, check: true).stdout()
+ conf_data.set_quoted('FULLCONFIG', feature_str)
+-conf_data.set_quoted('MPV_CONFDIR', join_paths(get_option('prefix'), get_option('sysconfdir'), 'mpv'))
++conf_data.set_quoted('MPV_CONFDIR', '/etc/mpv')
+ conf_data.set_quoted('PLATFORM', host_machine.system())
+ configure_file(output : 'config.h', configuration : conf_data)
+ message('List of enabled features: ' + feature_str)

flake.nix

@@ -46,8 +46,15 @@
     packages // rec {
       overlays.default = final: prev: let
         newScripts = packages.packages.${prev.system};
-      in {
-        mpv = prev.mpv.override { scripts = builtins.attrValues newScripts; };
+      in rec {
+        mpv-unwrapped = prev.mpv-unwrapped.overrideAttrs (oldAttrs: {
+          patches = (oldAttrs.patches or []) ++ [
+            ./confdir.patch
+          ];
+        });
+        mpv = prev.wrapMpv mpv-unwrapped {
+          scripts = builtins.attrValues newScripts;
+        };
         mpvScripts = prev.mpvScripts // newScripts;
       };