[PATCH 0/1] MR4642: configure: Use Wine includes for cross compiler checks.

[Jacek Caban (＠jacek)]

C99 checks depend on stddef.h and stdarg.h. Those headers are usually shipped with
compilers (and another copy of them as part of mingw-w64 for targets that use it),
but some providers skip them. We use our own version during the build anyway, so
we may use them for configure checks as well.