eclass: Add golang-* eclasses from gentoo upstream

These are used by some of the new packages like app-emulation/containerd and
app-emulation/runc etc. Taken at upstream commit
d9abb73c24f7bd9fb93fff5664e01ad2c7b4b4f1.

BUG=None
TEST=trybots

Change-Id: I3d54c866c44d66120fffdf93cdfb750670e25fb0
Reviewed-on: https://chromium-review.googlesource.com/344643
Commit-Ready: Aditya Kali <adityakali@google.com>
Tested-by: Aditya Kali <adityakali@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
4 files changed