gcc: enable ld.gold and ld.bfd (default)

GCC 4.8 allows both linkers available, and default can be changed
by passing -fuse-ld={gold,bfd} option to the driver.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
gcc: bump binutils version to 2.23.2

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
gcc: bump elfutils version to 0.156

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
elfutils: remove dead patches

The patches were intended for elfutils 0.155 and are already included
into 0.156.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #149 from davidlt/IB/CMSSW_7_0_X/devel-gcc48

[CMSSW_7_0_X][48] GCC updates