ff2mpv-go: use 'PATH' to invoke 'mpv'

Patching in the full-path to the binary is more robust, unfortunately
this means that a user of `ff2mpv-go` can't use their own wrapped `mpv`
without overriding the package.

As a practical example: using home-manager to configure `mpv` with
additional scripts will *not* work with the package as it was previously
written.

With this commit, we now rely on `PATH` lookups to find the `mpv`
binary, this should prioritize a user's customized `mpv`.

pkgs/by-name/ff/ff2mpv-go/package.nix

@@ -1,6 +1,7 @@
 { lib
 , buildGoModule
 , fetchgit
+, makeWrapper
 , mpv
 }:
 buildGoModule rec {
@@ -13,17 +14,21 @@ buildGoModule rec {
     hash = "sha256-e/AuOA3isFTyBf97Zwtr16yo49UdYzvktV5PKB/eH/s=";
   };
 
-  vendorHash = null;
+  nativeBuildInputs = [
+    makeWrapper
+  ];
 
-  postPatch = ''
-    substituteInPlace ff2mpv.go --replace '"mpv"' '"${lib.getExe mpv}"'
-  '';
+  vendorHash = null;
 
   postInstall = ''
     mkdir -p "$out/lib/mozilla/native-messaging-hosts"
     $out/bin/ff2mpv-go --manifest > "$out/lib/mozilla/native-messaging-hosts/ff2mpv.json"
   '';
 
+  postFixup = ''
+    wrapProgram $out/bin/ff2mpv-go --suffix PATH ":" ${lib.makeBinPath [ mpv ]}
+  '';
+
   meta = with lib; {
     description = "Native messaging host for ff2mpv written in Go";
     homepage = "https://git.clsr.net/util/ff2mpv-go/";