rapcad: Fix running of {pre,post}Configure

Commit 0055c6a introduced a new preConfigure hook that sets the right
qmake path. Unfortunately the mkDerivation attributes of rapcad
override the whole configurePhase, so this hook isn't run at all.

However, this still doesn't fix the build of rapcad, because it's unable
to find GL/glu.h.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/applications/graphics/rapcad/default.nix

@@ -15,8 +15,10 @@ stdenv.mkDerivation rec {
   buildInputs = [ qtbase cgal boost gmp mpfr flex bison dxflib readline ];
 
   configurePhase = ''
-    qmake;
+    runHook preConfigure
+    qmake
     sed -e "s@/usr/@$out/@g" -i $(find . -name Makefile)
+    runHook postConfigure
   '';
 
   meta = {