Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.Approved by: re (implicit)Sponsored by: The FreeBSD Foundation
Add a new machine independent varargs.h and use it as a central placeto announce the demise of varargs support in GCC versions 3.3+ and todirect users to stdarg.h instead.Fall back to machine/varargs.h for older GCC versions.