treewide: use runtimeShell instead of stdenv.shell whenever possible

Whenever we create scripts that are installed to $out, we must use runtimeShell
in order to get the shell that can be executed on the machine we create the
package for. This is relevant for cross-compiling. The only use case for
stdenv.shell are scripts that are executed as part of the build system.
Usages in checkPhase are borderline however to decrease the likelyhood
of people copying the wrong examples, I decided to use runtimeShell as well.

pkgs/games/worldofgoo/default.nix

@@ -1,25 +1,26 @@
 { stdenv, requireFile
 , libX11, libXext, libXau, libxcb, libXdmcp , SDL, SDL_mixer, libvorbis, libGLU_combined
+, runtimeShell
 , demo ? false }:
 
 # TODO: add i686 support
 
 stdenv.mkDerivation rec {
-  name = if demo 
+  name = if demo
     then "WorldOfGooDemo-1.41"
     else "WorldofGoo-1.41";
 
   arch = if stdenv.hostPlatform.system == "x86_64-linux" then "supported"
     else throw "Sorry. World of Goo only is only supported on x86_64 now.";
 
-  goBuyItNow = '' 
+  goBuyItNow = ''
     We cannot download the full version automatically, as you require a license.
     Once you bought a license, you need to add your downloaded version to the nix store.
     You can do this by using "nix-prefetch-url file://\$PWD/WorldOfGooSetup.1.41.tar.gz" in the
     directory where you saved it.
 
-    Or you can install the demo version: 'nix-env -i -A pkgs.worldofgoo_demo'. 
-  ''; 
+    Or you can install the demo version: 'nix-env -i -A pkgs.worldofgoo_demo'.
+  '';
 
   getTheDemo = ''
     We cannot download the demo version automatically. Please go to
@@ -28,8 +29,8 @@ stdenv.mkDerivation rec {
     directory where you saved it.
   '';
 
-  src = if demo 
-    then 
+  src = if demo
+    then
       requireFile {
          message = getTheDemo;
          name = "WorldOfGooDemo.1.41.tar.gz";
@@ -45,7 +46,7 @@ stdenv.mkDerivation rec {
   phases = "unpackPhase installPhase";
 
   # XXX: stdenv.lib.makeLibraryPath doesn't pick up /lib64
-  libPath = stdenv.lib.makeLibraryPath [ stdenv.cc.cc stdenv.cc.libc ] 
+  libPath = stdenv.lib.makeLibraryPath [ stdenv.cc.cc stdenv.cc.libc ]
     + ":" + stdenv.lib.makeLibraryPath [libX11 libXext libXau libxcb libXdmcp SDL SDL_mixer libvorbis libGLU_combined ]
     + ":" + stdenv.cc.cc + "/lib64";
 
@@ -60,7 +61,7 @@ stdenv.mkDerivation rec {
     #makeWrapper doesn't do cd. :(
 
     cat > $out/bin/WorldofGoo << EOF
-    #!${stdenv.shell}
+    #!${runtimeShell}
     cd $out/libexec/2dboy/WorldOfGoo
     exec ./WorldOfGoo.bin64
     EOF