merge revision(s) 57020,57021: [Backport #13014]
Add clang volatile fixes from FreeBSD and NetBSD. Use volatile instead of optnone to avoid optimization which causes segmentation faults. Patch by Dimitry Andric. [ruby-core:78531] [Bug #13014]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@57347 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 57020,57021: [Backport #13014]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@57347 b2dd03c8-39d4-4d8f-98ff-823fe69b080e