gccgo: gccgo 5.0 bin/go does not download transitive dependencies #10217
Description
lucky(~/devel/build) % /opt/gccgo/bin/go version
go version gccgo (GCC) 5.0.0 20150116 (experimental) linux/amd64
lucky(~/devel/build) % /opt/gccgo/bin/gccgo -v
Using built-in specs.
COLLECT_GCC=/opt/gccgo/bin/gccgo
COLLECT_LTO_WRAPPER=/opt/gccgo/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc/branches/gccgo/configure --prefix=/opt/gccgo --enable-languages=c,c++,go --disable-bootstrap
Thread model: posix
gcc version 5.0.0 20150116 (experimental) (GCC)
Using a freshly compile version of the go tool packaged with gccgo 5.0, it fails to download transitive dependencies
env GOPATH=/tmp/gopath /opt/gccgo/bin/go get -v github.com/juju/juju/...
github.com/juju/juju (download)
github.com/juju/juju
github.com/juju/juju/api/base
github.com/juju/juju/juju/arch
github.com/juju/juju/network
# github.com/juju/juju/api/base
/tmp/gopath/src/github.com/juju/juju/api/base/caller.go:7:23: error: import file ‘github.com/juju/names’ not found
"github.com/juju/names"
^
/tmp/gopath/src/github.com/juju/juju/api/base/caller.go:23:21: error: expected package
EnvironTag() (names.EnvironTag, error)
^
/tmp/gopath/src/github.com/juju/juju/api/base/caller.go:23:16: error: invalid named/anonymous mix
EnvironTag() (names.EnvironTag, error)
^
github.com/juju/juju/rpc/rpcreflect
github.com/juju/juju/cert
# github.com/juju/juju/cert
/tmp/gopath/src/github.com/juju/juju/cert/cert.go:19:24: error: import file ‘github.com/juju/errors’ not found
"github.com/juju/errors"
^
/tmp/gopath/src/github.com/juju/juju/cert/cert.go:38:14: error: reference to undefined name ‘errors’
return nil, errors.New("no certificates found")
... lots more output
These failures are because other packages in other repos have not been downloaded recursively as part of the go get process.