add introspection into GTK libs (part of #517)

This is all work of Marc Weber <marco-oweber@gmx.de>, except for a few nitpicks.

Tested space blowup: IMHO negligible to headers and similar stuff,
e.g. the firefox closure (reported by du) grows from 560 to 579 MB.
Saving space should be handled separately,
e.g. we have the multiple-outputs branch.
disable auto-detected introspection for libwnck and clutter

Didn't build as it was, and not needed anywhere AFAIK.
introspection disabling -- clutter-gtk, NM-applet, gnome_panel

Didn't build as it was, and not needed anywhere AFAIK.
qt, glew: propagate glu

After removing qt's dependency on the symlinked combination of mesa and glu,
many qt apps were missing it now (since e9f0d10).
I resove this to a compromise.
mesa: attempt to fix driverLink on darwin
introspection disabling -- libchamplain

Didn't build as it was, and not needed anywhere AFAIK.
darwin: attempt to fix pango via flattening cairo includes

Changes hash only on darwin.
pixman: Update to 0.30.2
otool: fix licenses, adding the new APSL 2.0 as well

Now Hydra can build glib introspection and all that depends on it
(just darwin).
gobjectIntrospection: fix build on darwin (close #832)

vcunat edit: SANE_MALLOC_PROTOS is gone, removing the handling
https://git.gnome.org/browse/glib/commit/?id=518e3104bf6cdb5d8e6b43d3b721805db5951139
glib: bugfix update (important for ext4 sync)
lcms2: "featured+maintenance" updates

I see nothing potentially dangerous in changelog, and packages seem to build and run.
ghostscript: minor update, a little refactoring

Builds fine, I tried running some apps depending on it.
binutils: Also enable plugins when building with gold.
llvm: Build the LLVMgold.so plugin for ld.gold &c.

Conflicts (simple):
	pkgs/development/compilers/llvm/default.nix
lcms2: update the hash

Upstream changed one line in the source, without bumping the version.
ghostscript: bugfix update (old tarball removed upstream)

There was some incompatibility problem with the last update,
so upstream retracted the previous release.
Merge branch 'master' into x-updates
tarball: add --show-trace on the remaining calls

This should help tracing some evaluation problems in future.
tarball: fix evaluation of qt on freebsd (mesa)