Introduce LLVM_FALLTHROUGH, which expands to the C++17 attribute.

This allows you to annotate switch case fallthrough in a better way
than a "// FALLTHROUGH" comment. Eventually it would be nice to turn
on -Wimplicit-fallthrough, if we can get the code base clean.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278868 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed