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.
The build was complaining:
meson.build:660: WARNING: Your libc does not have the C.UTF-8 locale and no other
suitable UTF-8 fallback locale could be found. You can still build GJS, but
some tests will fail.
The tests do not actually seem to be affected but still.
* Do not propagate spidermonkey, it is only needed gjs to link against.
* Split out dev output, any propagated dependencies should go there.
* Drop unnecessary sed, the readline thing is no longer there.
* Add passthru.tests to allow running installed tests easily.
* Drop pango from buildInputs, we only need it as a transitive dependency of gtk3 for installed tests; gjs actually depends on cairo.
* Move libxml2 to nativeBuildInputs, it is called by glib-compile-resources when xml-stripblanks preprocessing is used.
* Propagate glib, as it is in Requires in the pc file.
It is just 2.5 MB closure reduction but every megabyte counts.
