runtime: make printf work on misaligned stack
runtime: make printf work on misaligned stack

(Shouldn't happen, but if it does, it's useful to be
able to use printf to debug it.)

R=r
CC=golang-dev
http://codereview.appspot.com/4250057

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