use pc/ln table to print source lines in traceback

r45=; 6.out
oops
panic PC=0x400316
0x400316?zi /home/rsc/go/src/runtime/rt0_amd64_linux.s:83
	main·g(4195177, 0, 4205661, ...)
	main·g(0x400369, 0x402c5d, 0x403e49, ...)
0x40034c?zi /home/rsc/go/src/runtime/x.go:24
	main·f(4205661, 0, 4210249, ...)
	main·f(0x402c5d, 0x403e49, 0x1, ...)
0x400368?zi /home/rsc/go/src/runtime/x.go:37
	main·main(4210249, 0, 1, ...)
	main·main(0x403e49, 0x1, 0x7fff9d894bd8, ...)
0x402c5c?zi /home/rsc/go/src/runtime/rt0_amd64.s:70
	mainstart(1, 0, 2643020760, ...)
	mainstart(0x1, 0x7fff9d894bd8, 0x0, ...)
r45=;

R=r
DELTA=251  (198 added, 25 deleted, 28 changed)
OCL=19965
CL=19979