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).
qtcreator: Update to 2.8.1
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.
qtcreator: Make the qt package optional and introduce the QtSDK

To give the ability to use a different Qt version than the default one
(which can build 3 different times Qt Libraries if we mixed the default
one, the qtcreator one and the version including all the examples and the
docs).

Right now a developer can choose to directly install the QtSDK which
includes a "full" (developerBuild + docs + examples) Qt version and uses
it to build QtCreator.

The possibility to only install QtCreator and its previous behavior has
been kept for flexibility purposes (we do not need to force someone on the
SDK approach).
mesa: Minor fix on GL/gl.h

Apply a fix which prevented to use -DGL_GLEXT_LEGACY, -Werror and -Wundef
to be used together. This produced a build fail on any software meeting
these requirements.
Add Qt 5.1.1 and its SDK

Consider this as a first step towards the integration of Qt5 into nixpkgs,
it does not yet intends to replace Qt4 on every packages even if possible.
My goal here is to have a first derivation in common between people who
needs qt5 for development purposes.

The derivation has been written from scratch but I took care to read at the
version 4 to re-integrate some patches which are still compatible. However,
I did not had enough time to test gtkStyle and flashplayerFix as I do not
use any of them. Also, OSX users will have to do some extra work because
I do not have any mac.

Finally, as some configure flags have changed and in an hope to provide a
clear package definition before it becomes mature, I voluntary added some
flags which are default. Once every option will be mastered, we will just
have to redo a pass on qt5 configure flags and remove the ones which are
set by default.
Add text-format haskell library
Add Ubuntu 13.10
Add Fedora 19
Debian 6: Update to 6.0.8
Debian 7: Update to 7.2

Also rename "debian70" to "debian7" to reflect the Wheezy's new
versioning scheme.
Remove currently broken Debian mirror
Merge pull request #1113 from Zoomulator/master

Dropbox: updated to v2.4.3
Build RPMs for i686 rather than i386

The default target (i386-linux) causes flags like "-march i386" to be
added, which breaks on recent Fedora releases (18 and up), resulting
in errors like:

  /usr/lib/gcc/i686-redhat-linux/4.7.2/../../../../include/c++/4.7.2/ext/atomicity.h:48: undefined reference to `__atomic_fetch_add_4'

So set the target to i686-linux.

http://hydra.nixos.org/build/6567357
munin: fix documentation links
nixos-generate-config: Add --no-filesystems flag.

This is to get back the old behavior of nixos-hardware-scan, which
didn't include fileSystems and swapDevices.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
nixos-generate-config: Remove unnecessary spaces.

The attributes swapDevices and imports add a space character after the
eqals sign, which is unnecessary. I know, I'm a pedantic douche bag but
it hurts my eyes.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
nixos-generate-config: Add --show-hardware-config.

So, we get the old behaviour of nixos-hardware-scane if we run the
following command:

nixos-generate-config --no-filesystems --show-hardware-config

This allows to use scripts in order to fetch NixOS specific hardware
information, without the need to duplicate code elsewhere.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
synergy: Update to new upstream version 1.4.15.

This is a bugfix release which fixes the following bugs:

 * Synergy Service - Error 87: The parameter is incorrect.
 * Option not supported on Linux: --enable-drag-drop (server not
   starting)

Bug IDs and the announcement can be found at:

http://synergy-foss.org/blog/synergy-1-4-15-released/

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
nixos-rebuild: Drop references to <nixos>.

Commit 31203732b3104125e107a3141578399cab5d478f dropped the reference to
<nixos> from NIX_PATH (nixos/modules/programs/environment.nix) and thus
prevents systems that are not using channels from rebuilding.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>