port/systab.h		1991/0731		Created.
		1991/0806		Add sysrendezvous.
		1991/0807		Add sysrfork.
		1991/0926		Add sysctab.
		1991/1011		Add sysunmount.
		1991/1105		Format edit.
		1992/0309		Add new syswait.
		1992/0428		Add new sysrfork; remove old sys__wait__.
		1992/0430		Deprecate sysfork.
		1992/0603		Deprecate sysforkpgrp.
		1992/0622		Remove sys__fork__, sys__forkpgrp__, sys__rfork__.
		1992/0720		Use names sys_x1, sys_x2, sys_x3, probably to allow auto-generator of sys call numbers to work.
		1993/0209		Add sysfsession.
		1993/0210		Move sysfsession into _x1 slot.
		1993/0330		Add sysfauth.
		1993/1004		Add syspath.
		1993/1201		Add notes about NSYSCALL. (Look for bug?)
		1994/0322		Rename syspath to sysfd2path. Remove comments about NSYSCALL.
		1994/0402		Add syswrite9p.
		1994/0405		Add sysread9p.
		1994/0406		Remove blank syscall.
		1994/0407		Fix nsyscall to be computed correctly.
		1998/0319		Remove unused sysdeath prototype. Add sysvseek.
		1998/0916		Rename sysvseek to sysseek. Rename sysseek to sysoseek.
		1999/0812		Strange format edit; add systunnel and sysexportfs.
		1999/0813		Undo strange format edit.
		1999/1109		Remove systunnel, sysexportfs.
		2001/0223		Add syspread, syspwrite.
		2001/0527		Convert to 9P2000. Deprecate 9P1 system calls. Add 9P2000 system calls.
		2001/0819		Deprecate more 9P system calls. Add more 9P2000 calls.