new stacktrace format

new stacktrace format

sys·gosched+0x25 /home/rsc/go/src/runtime/proc.c:477
	sys·gosched()
chanrecv+0x29e /home/rsc/go/src/runtime/chan.c:277
	chanrecv(0x4be80, 0x0, 0x4cf88, 0x0, 0x0, ...)
sys·chanrecv1+0x5b /home/rsc/go/src/runtime/chan.c:355
	sys·chanrecv1(0x4be80, 0x0)
once·Server+0x26 /home/rsc/go/src/lib/strconv/atoi.go:-41
	once·Server()

the last line is broken (atoi.go:-41) but that's not new.

R=r
DELTA=46  (19 added, 14 deleted, 13 changed)
OCL=20018
CL=20026