var go/build.defaultToolTags

3 uses

	go/build (current package)
		build.go#L320: var defaultToolTags []string
		build.go#L345: 	defaultToolTags = append([]string{}, c.ToolTags...) // our own private copy
		build.go#L1142: 		ctxt.JoinPath != nil || ctxt.SplitPathList != nil || ctxt.IsAbsPath != nil || ctxt.IsDir != nil || ctxt.HasSubdir != nil || ctxt.ReadDir != nil || ctxt.OpenFile != nil || !equal(ctxt.ToolTags, defaultToolTags) || !equal(ctxt.ReleaseTags, defaultReleaseTags) {