This change moves the cgo support for go loader to a common
internal package that can be reused by go/packages. That
support is used to invoke cgo to process the files returned
by the fallback pre-go1.11 Go list.
The cgo processing does not propagate all of the config correctly.
We're building a go/build.Package to get the cgo command line
invocation and it might be incorrectly configured if the user's
configuration is different from go/build.Default.
Change-Id: I0de3c65cb723587e1551edeb77219614ba9650bf
Reviewed-on: https://go-review.googlesource.com/127816
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
Michael Matloob