gamin: switch to pname+version, cleanup

pkgs/development/libraries/gamin/default.nix

···
 { lib, stdenv, fetchurl, fetchpatch, pkg-config, glib, autoreconfHook }:
 
-let
-  cross = stdenv.hostPlatform != stdenv.buildPlatform;
-in stdenv.mkDerivation (rec {
-  name = "gamin-0.1.10";
+stdenv.mkDerivation rec {
+  pname = "gamin";
+  version = "0.1.10";
 
   src = fetchurl {
-    url = "https://www.gnome.org/~veillard/gamin/sources/${name}.tar.gz";
+    url = "https://www.gnome.org/~veillard/gamin/sources/gamin-${version}.tar.gz";
     sha256 = "18cr51y5qacvs2fc2p1bqv32rs8bzgs6l67zhasyl45yx055y218";
   };
 
···
     "CPPFLAGS=-D_GNU_SOURCE"
   ];
 
+  preBuild = lib.optionalString stdenv.isDarwin ''
+    sed -i 's/,--version-script=.*$/\\/' libgamin/Makefile
+  '';
+
   patches = [ ./deadlock.patch ]
     ++ map fetchurl (import ./debian-patches.nix)
     ++ lib.optional stdenv.cc.isClang ./returnval.patch
···
       name = "fix-pthread-mutex.patch";
       url = "https://git.alpinelinux.org/aports/plain/main/gamin/fix-pthread-mutex.patch?h=3.4-stable&id=a1a836b089573752c1b0da7d144c0948b04e8ea8";
       sha256 = "13igdbqsxb3sz0h417k6ifmq2n4siwqspj6slhc7fdl5wd1fxmdz";
-    }) ++ lib.optional (cross) ./abstract-socket-namespace.patch ;
+    }) ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) ./abstract-socket-namespace.patch;
 
 
   meta = with lib; {
···
   };
 }
 
-// lib.optionalAttrs stdenv.isDarwin {
-  preBuild =  ''
-    sed -i 's/,--version-script=.*$/\\/' libgamin/Makefile
-  '';
-})