Add optnone attribute for Clang#4716

Merged

bwbarrett merged 3 commits intoopen-mpi:v3.1.xfrom

rhc54:cmr31/optnone

Jan 31, 2018

Commits on Jan 15, 2018

Add the __optnone__ attribute to help avoid optimizing out MPIR_Breakpoint
Ralph Castain
committed
Fix the optnone attribute, add extension attribute
Ralph Castain
committed

Commits on Jan 24, 2018

opal_check_attributes: fix __extension__ test
jsquyres
committed