C++1y sized deallocation: if we have a use, but not a definition, of a sized
deallocation function (and the corresponding unsized deallocation function has
been declared), emit a weak discardable definition of the function that
forwards to the corresponding unsized deallocation.

This allows a C++ standard library implementation to provide both a sized and
an unsized deallocation function, where the unsized one does not just call the
sized one, for instance by putting both in the same object file within an
archive.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194055 91177308-0d34-0410-b5e6-96231b3b80d8
Remove stray comma from documentation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194056 91177308-0d34-0410-b5e6-96231b3b80d8
Lex: Require that '#' be followed by a macro parameter name when preceded by '##'

After lexing a '##', we would look ahead and check to see if it was
followed by '__VA_ARGS__'.  After doing so, we would then go ahead and
lex the token.

However we would fail in the case where the '##' was followed by a '#'
followed by an identifier because we would have lexed the '#' separately
from the identifier, bypassing our parameter validation logic.

Instead, lex the tokens coming after the '##' later.

This fixes PR17804.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194059 91177308-0d34-0410-b5e6-96231b3b80d8