squid: build without -Werror to fix build on GCC 4.8.x
aterm-2.8: add comment about build failures with gcc 4.8.x
bup: update to version 0.25-rc1-107-g96c6fa2 and drop -Werror to fix the build

  /nix/store/4jfqcb4mzh3vl08zgfh9ir46jii7rcb9-python-2.7.3/include/python2.7/modsupport.h:27:1: error: 'PyArg_ParseTuple' is an unrecognized format function type [-Werror=format=]
   PyAPI_FUNC(int) PyArg_ParseTuple(PyObject *, const char *, ...) Py_FORMAT_PARSETUPLE(PyArg_ParseTuple, 2, 3);
   ^
  cc1: all warnings being treated as errors
libgdiplus: fix download URL for 'libgdiplus-2.10.1-libpng15.patch'
flac: update download URL for build fix patch
release-small.nix: switch Emacs 23 to 24
release-small.nix: drop the Emacs 23.x packages from this file

Most of these packages are very old and don't compile in 'master' to
begin with, so it's probably not necessary to use them for testing the
stdenv-updates branch.
grub: fix download URL for grub-0.97-once.patch
elfutils: disable -Werror to fix the build

  nm.c: In function 'show_symbols_sysv':
  nm.c:773:27: error: argument to 'sizeof' in 'snprintf' call is the same expression as the destination; did you mean to provide an explicit length? [-Werror=sizeof-pointer-memaccess]
      snprintf (name, sizeof name, "[invalid sh_name %#" PRIx32 "]",
                             ^
  cc1: all warnings being treated as errors
iproute: don't compile with -Werror

  lnstat.c:169:30: error: argument to 'sizeof' in 'memset' call is the same expression as the destination; did you mean to provide an explicit length? [-Werror=sizeof-pointer-memaccess]
     memset(th.hdr[i], 0, sizeof(th.hdr[i]));
                                ^
  cc1: all warnings being treated as errors
  make[1]: *** [lnstat.o] Error 1