qt5: factor out common definitions and remove symlink farm

The module definitions are factored out and shared between qt56 and qt59. The
symlink farm which was created during builds is no longer needed.

pkgs/development/libraries/qt-5/qtModule.nix

@@ -0,0 +1,59 @@
+{ lib, mkDerivation, perl }:
+
+let inherit (lib) licenses maintainers platforms; in
+
+{ self, srcs, patches }:
+
+args:
+
+let
+  inherit (args) name;
+  version = args.version or srcs."${name}".version;
+  src = args.src or srcs."${name}".src;
+in
+
+mkDerivation (args // {
+  name = "${name}-${version}";
+  inherit src;
+  patches = args.patches or patches."${name}" or [];
+
+  nativeBuildInputs = (args.nativeBuildInputs or []) ++ [ perl self.qmake ];
+  propagatedBuildInputs = args.qtInputs ++ (args.propagatedBuildInputs or []);
+
+  outputs = args.outputs or [ "out" "dev" ];
+  setOutputFlags = args.setOutputFlags or false;
+
+  preHook = ''
+    . ${./hooks/move-qt-dev-tools.sh}
+    . ${./hooks/fix-qt-builtin-paths.sh}
+  '';
+
+  preConfigure = ''
+    ${args.preConfigure or ""}
+
+    fixQtBuiltinPaths . '*.pr?'
+  '';
+
+  postFixup = ''
+    if [ -d "''${!outputDev}/lib/pkgconfig" ]; then
+        find "''${!outputDev}/lib/pkgconfig" -name '*.pc' | while read pc; do
+            sed -i "$pc" \
+                -e "/^prefix=/ c prefix=''${!outputLib}" \
+                -e "/^exec_prefix=/ c exec_prefix=''${!outputBin}" \
+                -e "/^includedir=/ c includedir=''${!outputDev}/include"
+        done
+    fi
+
+    moveQtDevTools
+
+    ${args.postFixup or ""}
+  '';
+
+  meta = {
+    homepage = http://www.qt.io;
+    description = "A cross-platform application framework for C++";
+    license = with licenses; [ fdl13 gpl2 lgpl21 lgpl3 ];
+    maintainers = with maintainers; [ qknight ttuegel periklis ];
+    platforms = platforms.unix;
+  } // (args.meta or {});
+})