gc: resolve built-ins to built-in symbol
gc: resolve built-ins to built-in symbol

R=lvd
CC=golang-dev
http://codereview.appspot.com/5480049

pombredanne/go-deleteme,gnanderson/go,tv42/old-go,dsriram/golang,apparentlymart/golang,dsriram/golang,dsriram/golang,apparentlymart/golang,gnanderson/go,dsriram/golang,gnanderson/go,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,gnanderson/go,dsriram/golang,gnanderson/go,gnanderson/go,apparentlymart/golang,apparentlymart/golang,dsriram/golang,apparentlymart/golang,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,dsriram/golang,apparentlymart/golang,tv42/old-go,pombredanne/go-deleteme,pombredanne/go-deleteme,tv42/old-go