qwt: add version 6.x (we already have 5.x)

'qgis', one of the few 'qwt' dependees in nixpkgs, fails to build with
qwt 6. So I'm not moving the default version away from 5.x. Also, not
changing the default allows easy/safe cherry-picking to the stable
branch.

pkgs/development/libraries/qwt/6.nix

@@ -0,0 +1,27 @@
+{ stdenv, fetchurl, qt4 }:
+
+stdenv.mkDerivation rec {
+  name = "qwt-6.1.0";
+
+  src = fetchurl {
+    url = "mirror://sourceforge/qwt/${name}.tar.bz2";
+    sha256 = "00klw6jsn8z3dnhxg52pqg3hg5mw2sih8prwjxm1hzcivgqxkqx7";
+  };
+
+  propagatedBuildInputs = [ qt4 ];
+
+  postPatch = ''
+    sed -e "s|QWT_INSTALL_PREFIX.*=.*|QWT_INSTALL_PREFIX = $out|g" -i qwtconfig.pri
+  '';
+
+  configurePhase = "qmake -after doc.path=$out/share/doc/${name} -r";
+
+  meta = with stdenv.lib; {
+    description = "Qt widgets for technical applications";
+    homepage = http://qwt.sourceforge.net/;
+    # LGPL 2.1 plus a few exceptions (more liberal)
+    license = "Qwt License, Version 1.0";
+    platforms = platforms.linux;
+    maintainers = [ maintainers.bjornfor ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -5776,6 +5776,8 @@ let
 
   qwt = callPackage ../development/libraries/qwt {};
 
+  qwt6 = callPackage ../development/libraries/qwt/6.nix { };
+
   rabbitmq-c = callPackage ../development/libraries/rabbitmq-c {};
 
   raul = callPackage ../development/libraries/audio/raul { };