attr: inline syscall patch

Unfortunately the output of git.savannah.nongnu.org changes with each
gitweb update. This means that the current has
“0gja54fz79a9ma6b4mprnjxq77l5yg2z9xknlwhmkcrfnam02qxp” is no longer
correct:

$ nix-prefetch-url
https://git.savannah.nongnu.org/cgit/attr.git/patch/\?id=14adc898a36948267bfe5c63b399996879e94c98
1g8sky52rjg9fpmrddza1af89s9qd4bzsbxqb7mc5bv8gyh10s1k

Normally, we use fetchpatch to strip this out, but unfortunately attr
cannot use fetchpatch due to being used in bootstrapping fetchurl.
That is, it can’t use a custom postFetch since <nix/fetchurl.nix>
doesn’t support that.

To solve this problem, just inline the patch for now.

pkgs/development/libraries/attr/default.nix

@@ -14,10 +14,7 @@ stdenv.mkDerivation rec {
 
   patches = [
     # fix fakechroot: https://github.com/dex4er/fakechroot/issues/57
-    (fetchurl {
-      url = "https://git.savannah.nongnu.org/cgit/attr.git/patch/?id=14adc898a36948267bfe5c63b399996879e94c98";
-      sha256 = "0gja54fz79a9ma6b4mprnjxq77l5yg2z9xknlwhmkcrfnam02qxp";
-    })
+    ./syscall.patch
   ];
 
   postPatch = ''