libcommuni: Fix finding qmake

Commit 0055c6a introduced a new preConfigure hook that sets the right
qmake path.

As the configurePhase is replaced by a qmake path directly from qtbase,
it won't work because the setup-hook from qtbase needs to do some setup
in order for qmake to find its own data files.

So instead of hardcoding that path, we just go for setting the
configureFlags attribute and replacing which with "type -P" so that the
configure script can figure out the right path to qmake on its own.

This fixes the build of libcommuni and it now successfully compiles on
my machine.

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

pkgs/development/libraries/libcommuni/default.nix

@@ -15,11 +15,12 @@ stdenv.mkDerivation rec {
 
   enableParallelBuild = true;
 
-  configurePhase = ''
-    sed -i -e 's|/bin/pwd|pwd|g' configure
-    ./configure -config release -prefix $out -qmake ${qt5.qtbase}/bin/qmake
+  postPatch = ''
+    sed -i -e 's|/bin/pwd|pwd|g' -e 's/which/type -P/' configure
   '';
 
+  configureFlags = [ "-config release" ];
+
   meta = with stdenv.lib; {
     description = "A cross-platform IRC framework written with Qt";
     homepage = https://communi.github.io;