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 commit removes a patch from the derivation for libsigc++-2.0 that
appended -std=c++11 to the pkg-config file.
The patch in question orginated from the Debian project to enforce
-std=c++11 in projects using libsigc++-2.0 via pkg-config. This patch
was removed in 2016 when Debian switched to GCC 6.
This fixesNixOS/nixpkgs#33534.
URLs to http://nix.cs.uu.nl/dist/tarballs. With content-addressable
mirror support (r9190, NIXPKGS-70) this is no longer necessary:
fetchurl will try to download from that location automatically. So
we can keep the original URLs.
svn path=/nixpkgs/trunk/; revision=9192