/* vadefs.h, where Microsoft's C runtime says how a variable argument list is walked.
*
* The MSVC toolset's copy is used, and one line of it is changed. On x64 it starts a list with
* `__va_start(&ap, x)`, which is a function to nobody but cl.exe: cl turns the call into the
* address of the home slot after `x`, and no library defines it. clang knows the name as a builtin.
* This compiler knows `__builtin_va_start` instead, and on the Windows rows its `va_list` is the
* `char *` Microsoft's is, so the one macro is pointed at that and the rest of the header, which
* walks the list with pointer arithmetic, stands as written. The universal CRT's inline `printf`
* family starts every list through this macro.
*
* Anywhere else the name belongs to the library, and mingw-w64 has a vadefs.h of its own.
*/