treewide: use scons setup hook

Lots of packages can use it. Here is the list:

- jackmix
- klick
- mixx
- nova-filters
- rhvoice
- giv
- mypaint
- swift-im
- bombono
- mapnik
- serf
- nuitka
- pyexiv2
- godot
- hammer
- toluapp
- btanks
- dxx-rebirth
- endless-sky
- globulation
- the-powder-toy
- fceux
- gpsd
- mongodb
- rippled
- mariadb
- lprof

pkgs/applications/audio/jackmix/default.nix

@@ -17,12 +17,8 @@ stdenv.mkDerivation rec {
     jack
   ];
 
-  buildPhase = ''
-    scons
-  '';
   installPhase = ''
-    mkdir -p $out/bin
-    cp jackmix/jackmix $out/bin
+    install -D jackmix/jackmix $out/bin/jackmix
   '';
 
   meta = {