bison: prefer the tar.gz variant of the sources

Apparently, the bootstrapping stdenv cannot unpack xz-compressed tarfiles.
Merge remote-tracking branch 'official/master' into stdenv-updates
Merge remote-tracking branch 'origin/master' into stdenv-updates.
bison-3.x: fix build for good this time

 - Bison 3.x no longer compiles without Perl.

 - Don't try to run the test suite unless flex is available.
gstreamer: builds only with bison 2.x
all-packages.nix: string trailing whitespace
cln: update to version 1.3.3 to fix build with gcc 4.8.x.
esniper: fix build on darwin
Revert "binutils: minor update 2.23.1 -> .2"

This reverts commit 15f96c840f5ce71da5cb556d1aa76654e6b12dae.
See #909.

Conflicts (trivial, auto-resolved):
	pkgs/development/tools/misc/binutils/default.nix
ghc-7.6.3: cosmetic change to force a re-build
Fix gfortran 4.7 build: texinfo 5.1 is not supported.
gfortran: update to 4.8.1
ghc-7.6.3: undo commit 7c8ba75

The change was supposed to trigger a re-build to fix a broken GHC binary
on the Hydra build farm, but now it turns out that the cause for the
errors we're seeing isn't GHC: all kinds of (non-Haskell) packages are
broken.
gnum4: update to version 1.4.17
gnum4: fix download URL
gnum4: drop obsolete patches
Merge remote-tracking branch 'origin/master' into stdenv-updates.

Conflicts:
	pkgs/development/libraries/gettext/default.nix
gettext: fix minor errors after merge
gettext: strip trailing whitespace
llvm: add support for R600

It will be useful for mesa >= 9.2.*
Also, I want to restart the build on Hydra, as it succeeds for me.