broken and fixing it only creates a duplicate of what is already
in the FreeBSD kernel. Therefore, map the syscall directly to
getpgid().
PR: kern/21402
Submitted by: Christian Weisgerber <naddy@mips.inka.de>
While here, redefine the second entry for setpgid() so that we
don't need a stub. This is achieved by giving the second instance
the type NODEF.