[Bug lto/70955] [6/7 Regression] Wrong code generation for __builtin_ms_va_list with -flto

[ssbssa at yahoo dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70955

--- Comment #11 from Domani Hannes <ssbssa at yahoo dot de> ---
I can confirm that this patch works for windows as well.