This solves the following build failure with go-tools-0_pre20180817:
src/github.com/golang/lint/lint.go:25:2: cannot find package "golang.org/x/tools/go/gcimporter15" in any of:
/usr/lib/go/src/golang.org/x/tools/go/gcimporter15 (from $GOROOT)
/var/tmp/portage/dev-go/golint-0_pre20161114/work/golint-0_pre20161114/src/golang.org/x/tools/go/gcimporter15 (from $GOPATH)
/usr/lib/go-gentoo/src/golang.org/x/tools/go/gcimporter15
Package-Manager: Portage-2.3.49, Repoman-2.3.10
-# Copyright 1999-2017 Gentoo Foundation
+# Copyright 1999-2018 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
EAPI=6
SLOT="0/${PVR}"
IUSE=""
DEPEND=">=dev-lang/go-1.6
- dev-go/go-tools"
+ <dev-go/go-tools-0_pre20180817"
RDEPEND="!<dev-lang/go-1.6
dev-go/go-tools:="