cgo: rename C names for Go types to avoid conflicting with package
cgo: rename C names for Go types to avoid conflicting with package

Fixes issue 3371.

R=rsc, bsiegert, r, mtj, iant
CC=golang-dev
http://codereview.appspot.com/6131060

firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old