[Bug target/50818] va_list is filled incorrectly in functions with ms_abi attribute on amd64

[steven.shi at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50818

--- Comment #6 from Steven Shi <steven.shi at intel dot com> ---
BTW, latest LLVM/Clang 3.8 release has fixed this va_list ms_abi issue, please
see below email thread. Does GCC really cannot fix it as LLVM/Clang? This issue
really impact Uefi firmware building with GCC.

http://lists.llvm.org/pipermail/llvm-dev/2016-January/093778.html