Backport of clang fixes from CMSSW_7_1_CLANG_X branch

Trivial bugfixes back ported from the CMSSW_7_1_CLANG_X branch. These are the ones which are "just fine" and unambiguous. There are still a few fixes in the above mentioned branch which will need backport but they will be done in a separate pull request since they non-trivially change implementation.