checkpointing stuff

checkpointing stuff

SCCS-vsn: usr.bin/window/wwflush.c 3.13
SCCS-vsn: usr.bin/window/wwend.c 3.18
SCCS-vsn: usr.bin/window/wwiomux.c 3.27
SCCS-vsn: usr.bin/window/tt.h 3.29
SCCS-vsn: usr.bin/window/ttoutput.c 3.10
SCCS-vsn: usr.bin/window/ttzapple.c 3.13
SCCS-vsn: usr.bin/window/wwinit.c 3.42
SCCS-vsn: usr.bin/window/wwsuspend.c 3.17
SCCS-vsn: usr.bin/window/xxflush.c 3.7
SCCS-vsn: usr.bin/window/ttinit.c 3.28
SCCS-vsn: usr.bin/window/xx.c 3.7
SCCS-vsn: usr.bin/window/lcmd2.c 3.26
SCCS-vsn: usr.bin/window/compress.c 3.8
SCCS-vsn: usr.bin/window/wwrint.c 3.14
SCCS-vsn: usr.bin/window/ww.h 3.67