Avoid concepts when __cpp_lib_concepts isn't defined - #1749

Avoid concepts when __cpp_lib_concepts isn't defined#1749

Stephan T. Lavavej (StephanTLavavej) merged 3 commits into

microsoft:mainmicrosoft/STL:mainfrom

StephanTLavavej:use_sfinaeStephanTLavavej/STL:use_sfinaeCopy head branch name to clipboard