Apparently the darwin/386 builder does not enable cgo.
This failure turned up running

	GOARCH=386 GOHOSTARCH=386 ./all.bash

on my Mac.

Change-Id: Ia2487c4fd85d4b0f9f564880f22d9fde379946c3
Reviewed-on: https://go-review.googlesource.com/18859Reviewed-by: Ian Lance Taylor <iant@golang.org>