[Bug go/70597] New: [6 Regression] cmd/go: deduplicate gccgo afiles by package path, not *Package

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70597

            Bug ID: 70597
           Summary: [6 Regression] cmd/go: deduplicate gccgo afiles by
                    package path, not *Package
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: doko at gcc dot gnu.org
                CC: cmang at google dot com
  Target Milestone: ---

see https://go-review.googlesource.com/#/c/21692/

fixes building the golang-goprotobuf package with gccgo, which worked with GCC
5.

original report at
https://bugs.launchpad.net/ubuntu/+source/gccgo-6/+bug/1566552