CXXFeatures: fix elseif()
Merge topic 'cxx11' into next

7b140e6 CXXFeatures: fix elseif()
CXXFeatures: update list of expected compiler features
Merge topic 'cxx11' into next

124c4a2 CXXFeatures: update list of expected compiler features
CXXFeatures: update expected g++ results
Merge topic 'cxx11' into next

b098ab5 CXXFeatures: update expected g++ results