This turns the GCC clobbered error into a warning which should fix:
```
emanage_store.c: In function 'semanage_exec_prog':
semanage_store.c:1278:6: error: variable 'i' might be clobbered by 'longjmp' or 'vfork' [8;;https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wclobbered-Werror=clobbered8;;]
1278 | int i;
| ^
cc1: all warnings being treated as errors
```
continuation of #109595
pkgconfig was aliased in 2018, however, it remained in
all-packages.nix due to its wide usage. This cleans
up the remaining references to pkgs.pkgsconfig and
moves the entry to aliases.nix.
python3Packages.pkgconfig remained unchanged because
it's the canonical name of the upstream package
on pypi.
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
