cmd/ld: when using host linker pass -r option as -rpath
cmd/ld: when using host linker pass -r option as -rpath

R=golang-dev, daniel.morsing
CC=golang-dev
https://codereview.appspot.com/8070043

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