__builtin_va_*() and __builtin_ms_va_*() are declared as functions with a
parameter of reference type.
This patch fixes a crash when using these functions in C where an argument
of structure type is incompatible with the parameter type.
Differential Revision: https://reviews.llvm.org/D82805
Reviewed By: riccibruno
Patch by: Aleksandr Platonov <platonov.aleksandr@huawei.com>
Aleksandr Platonov