Changes

Summary

1. [c++2a] Treat 'concept' and 'requires' as keywords, add compat warning for C++17 and before.

Revision 310803 by rsmith: [c++2a] Treat 'concept' and 'requires' as keywords, add compat warning for C++17 and before.
Change Type	Path in Repository	Path in Workspace
	/cfe/trunk/include/clang/Basic/DiagnosticGroups.td	clang.src/include/clang/Basic/DiagnosticGroups.td
	/cfe/trunk/include/clang/Basic/DiagnosticLexKinds.td	clang.src/include/clang/Basic/DiagnosticLexKinds.td
	/cfe/trunk/include/clang/Basic/TokenKinds.def	clang.src/include/clang/Basic/TokenKinds.def
	/cfe/trunk/lib/Basic/IdentifierTable.cpp	clang.src/lib/Basic/IdentifierTable.cpp
	/cfe/trunk/lib/Lex/Preprocessor.cpp	clang.src/lib/Lex/Preprocessor.cpp
	/cfe/trunk/test/Lexer/keywords_test.cpp	clang.src/test/Lexer/keywords_test.cpp