gorebuild prints absolute paths instead of import paths

[joneskoo]

I have renamed my $GOPATH. For most binaries that are from the previous path, gorebuild -n shows absolute directory paths rather than import paths.

If there isn't an actual import path stored in the binary, maybe there should be? I filed a related issue golang/go#16814 just before finding gorebuild on Twitter.

I think there's value in storing the ACTUAL import path. Whether should go to a binary or a manifest file, I'm not 100%. Any thoughts?

Deriving the import path from GOPATH and source paths in the file is hacky and wouldn't work if you got the binary built by someone else (although arguably neither would an external manifest; which would support actually putting the import path in the binary).