go/ssa/interp: add syscall.Readlink intrinsic, needed by os package
go/ssa/interp: add syscall.Readlink intrinsic, needed by os package

Change-Id: Ie408fd5ffb2be2d60773eb3fda91912887df0a7e
Reviewed-on: https://go-review.googlesource.com/33147
Reviewed-by: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

syreclabs/go-tools,syreclabs/go-tools,golang/tools,syreclabs/go-tools,syreclabs/go-tools,golang/tools,golang/tools,syreclabs/go-tools,golang/tools,golang/tools,syreclabs/go-tools