Variadic templates are fully implemented.

Turn on the __has_feature switch for variadic templates, document
their completion, and put the ExtWarn into the c++0x-extensions
warning group.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123854 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed