machine/stdarg.h is deprecated and will be removed in due course.
This deorbits machine/stdarg.h and use sys/stdarg.h instead.
Not bumping PORTREVISION, as this is a build fix for future
removal of machine/stdarg.h and shouldn't cause changes
in contents of pkgs.
Co-authored-by: Brooks Davis <brooks@FreeBSD.org>
PR: 300622