pkgsMusl.screen: fix build

The patch was causing the build to fail.

The description of the gist the patch is from says:

> Patch for GNU Screen HEAD on OS X, which disables the error message
> "/var/run/utmp: No such file or directory" on launch.

I don't see that message with pkgsMusl.screen, so I think we don't
need the patch any more.

pkgs/tools/misc/screen/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, fetchpatch, autoreconfHook, ncurses, utmp, pam ? null }:
+{ lib, stdenv, fetchurl, autoreconfHook, ncurses, utmp, pam ? null }:
 
 stdenv.mkDerivation rec {
   pname = "screen";
@@ -16,13 +16,6 @@ stdenv.mkDerivation rec {
     "--enable-colors256"
   ];
 
-  patches = lib.optional stdenv.hostPlatform.isMusl
-    (fetchpatch {
-      url = "https://gist.githubusercontent.com/yujinakayama/4608863/raw/76b9f89af5e5a2e97d9a0f36aac989fb56cf1447/gistfile1.diff";
-      sha256 = "0f9bf83p8zdxaa1pr75jyf5g8xr3r8kv7cyzzbpraa1q4j15ss1p";
-      stripLen = 1;
-    });
-
   nativeBuildInputs = [
     autoreconfHook
   ];