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/compression/pixz/default.nix

@@ -1,6 +1,6 @@
-{ 
+{
   stdenv, fetchFromGitHub, autoconf, automake, libtool, pkgconfig
-  , asciidoc, libxslt, libxml2, docbook_xml_dtd_45, docbook_xml_xslt
+  , asciidoc, libxslt, libxml2, docbook_xml_dtd_45, docbook_xsl
   , libarchive, lzma
 }:
 stdenv.mkDerivation rec {
@@ -11,7 +11,7 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [
     autoconf automake libtool asciidoc libxslt libxml2
-    docbook_xml_dtd_45 docbook_xml_xslt
+    docbook_xml_dtd_45 docbook_xsl
     libarchive lzma
   ];
   preBuild = ''