Disable exec symlink resolution for PostgreSQL 9.2

When building PostgreSQL with plugins under NixOS, NixOS will create a
postgresql-and-plugins directory which symlinks PostgreSQL and all the plugins
into a single directory. Unfortunately, the plugins will not actually be usable
by PostgreSQL because it will still try and locate them in the original
PostgreSQL share directory, not postgresql-and-plugins.

In this commit, I have patched resolve_symlinks to always return success, which
matches the behavior if HAVE_READLINK is false (so presumably invalid paths are
never passed to this function).
nixos/nginx: allow to specify which package to use

This enables to override which plugins to include with nginx by allowing to change
nginx package. I also removed webdav option in nginx nixos module, because you
can now specify this by overriding nginx package.
Attempt at compiling MilkyTracker, but recent zlib version may have broken it.

There's a zlib version included with milkytracker,
but there's no makefiles for it. I've only included
the header here, but it fails at link-time with
several 'undefined reference' errors, which simply
means it can't find the definitions, e.g. compiled
zlib.
There's bug reports on other package systems although
unfortunately still unresolved.
https://bugs.archlinux.org/task/31324
http://lists.freebsd.org/pipermail/freebsd-ports/2013-March/082180.html
MilkyTracker: fix build, use system zlib and decompressor patch

Also add JACK support
MilkyTracker: Tidy up, sort buildInputs and use the attrPath for the license
fetchsvn: handle redirect(s)

Instead of failing if the server redirects us to a new URL, accept up to
2 redirects by printing 2 extra p's to subversion.
Make touchpad button mapping configurable
Add serverFlagsSection parameter to the xserver config
adobe-reader: Update to 9.5.5
SDL2: update to v2.0.1
offlineimap: update to (latest) 6.5.5
Resurrect the old ghcWithPackages wrapper under the attribute name 'ghcWithPackagesOld'.
SDL2: clean configure flags.

I removed some flags that are no longer present, one that was redundant
(default value) and added a comment regarding why enable-static is there.
Add qvim - an experimental Qt gui for Vim

vim-qt has the most complete set of Ctrl-Alt-Meta binding functionality.
For example, qvim is able to correctly bind keys like Alt-<nonlatin>.
More: https://bitbucket.org/equalsraf/vim-qt/wiki/Features
socate: Update to 1.7.2.2, 2.0.0-b6

CVE-2013-3571
apache-httpd: Update to 2.4.6
Remove some unsupported platforms
Don't build some packages on some platforms
Allow packages to be marked as "broken" by setting meta.broken

The effect is that they won't show up in "nix-env -qa" anymore.
Don't build Linux 3.6-rpi packages on Hydra

They're all broken.