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/development/libraries/mailcore2/default.nix

@@ -1,5 +1,5 @@
 { stdenv, lib, fetchFromGitHub, cmake, libetpan, icu, cyrus_sasl, libctemplate
-, libuchardet, pkgconfig, glib, libtidy, libxml2, libuuid, openssl
+, libuchardet, pkgconfig, glib, html-tidy, libxml2, libuuid, openssl
 }:
 
 stdenv.mkDerivation rec {
@@ -17,14 +17,14 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [
     libetpan cmake icu cyrus_sasl libctemplate libuchardet glib
-    libtidy libxml2 libuuid openssl
+    html-tidy libxml2 libuuid openssl
   ];
 
   postPatch = ''
     substituteInPlace CMakeLists.txt \
        --replace " icule iculx" "" \
        --replace "tidy/tidy.h" "tidy.h" \
-       --replace "/usr/include/tidy" "${libtidy}/include" \
+       --replace "/usr/include/tidy" "${html-tidy}/include" \
        --replace "/usr/include/libxml2" "${libxml2.dev}/include/libxml2"
     substituteInPlace src/core/basetypes/MCHTMLCleaner.cpp \
       --replace buffio.h tidybuffio.h