FWCore: add support for Address Sanitizer IBs

The following adds support for Address Sanitizer (asan) IBs using
mainstream branch. Because a full stack of CMSSW is not compiled with
ASan we need some extra steps. ASan run-time must be linked into
main executables statically to force early ASan initialization.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #5329 from davidlt/from-CMSSW_7_2_X_2014-09-17-0200

FWCore: add support for Address Sanitizer IBs
Changes needed because of changes in the API for clang v3.5