treewide: remove aliases in nixpkgs

This makes the command ‘nix-env -qa -f. --arg config '{skipAliases =
true;}'’ work in Nixpkgs.

Misc...

- qtikz: use libsForQt5.callPackage

  This ensures we get the right poppler.

- rewrites:

  docbook5_xsl -> docbook_xsl_ns
  docbook_xml_xslt -> docbook_xsl

diffpdf: fixup

pkgs/tools/graphics/luxcorerender/default.nix

@@ -3,7 +3,7 @@
 , freetype, openexr, libXdmcp, libxkbcommon, epoxy, at-spi2-core
 , dbus, doxygen, qt5, c-blosc, libGLU, gnome3, pcre
 , bison, flex, libpthreadstubs, libX11
-, embree2, makeWrapper, gsettings_desktop_schemas, glib
+, embree2, makeWrapper, gsettings-desktop-schemas, glib
 , withOpenCL ? true , opencl-headers, ocl-icd, opencl-clhpp
 }:
 
@@ -31,7 +31,7 @@ in stdenv.mkDerivation rec {
      flex libX11 libpthreadstubs python35 libXdmcp libxkbcommon
      epoxy at-spi2-core dbus doxygen
      # needed for GSETTINGS_SCHEMAS_PATH
-     gsettings_desktop_schemas glib gnome3.gtk
+     gsettings-desktop-schemas glib gnome3.gtk
      # needed for XDG_ICON_DIRS
      gnome3.defaultIconTheme
      makeWrapper