treewide: preset windres missing to fix builds on Linux

https://github.com/NixOS/nixpkgs/pull/30484#issuecomment-345899910

pkgs/applications/audio/schismtracker/default.nix

···
     sha256 = "1ny7wv2wxm1av299wvpskall6438wjjpadphmqc7c0h6d0zg5kii";
   };
 
+  preConfigure = ''
+    # Build fails on Linux with windres.
+    export ac_cv_prog_ac_ct_WINDRES=
+  '';
+
   configureFlags = "--enable-dependency-tracking";
 
   buildInputs = [ alsaLib python SDL ];
+
+  enableParallelBuilding = true;
 
   meta = {
     description = "Music tracker application, free reimplementation of Impulse Tracker";

pkgs/applications/science/astronomy/gravit/default.nix

···
 
   nativeBuildInputs = [ autoconf automake ];
 
-  preConfigure = "./autogen.sh";
+  preConfigure = ''
+    ./autogen.sh
+
+    # Build fails on Linux with windres.
+    export ac_cv_prog_WINDRES=
+  '';
+
+  enableParallelBuilding = true;
 
   meta = {
     homepage = http://gravit.slowchop.com;

pkgs/games/freedink/default.nix

···
     pkgconfig intltool fontconfig libzip zip zlib
   ];
 
+  preConfigure = ''
+    # Build fails on Linux with windres.
+    export ac_cv_prog_ac_ct_WINDRES=
+  '';
+
   postInstall = ''
     mkdir -p "$out/share/"
     ln -s ${freedink_data}/share/dink "$out/share/"
   '';
+
+  enableParallelBuilding = true;
 
   meta = {
     description = "A free, portable and enhanced version of the Dink Smallwood game engine";

pkgs/games/macopix/default.nix

···
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [ gtk openssl ];
 
+  preConfigure = ''
+    # Build fails on Linux with windres.
+    export ac_cv_prog_WINDRES=
+  '';
+
+  enableParallelBuilding = true;
+
   meta = {
     description = "Mascot Constructive Pilot for X";
     homepage = http://rosegray.sakura.ne.jp/macopix/index-e.html;