Stop modifying upstream .gitignore file and put build artifacts in debian/.build/upstream

[ottok]

See commits for details. This is a re-submission of #230, pending to be merged potentially in the summer of 2025.

Note that these two changes should stay aligned:

• https://salsa.debian.org/go-team/packages/dh-golang/-/merge_requests/26
• https://github.com/Debian/dh-make-golang/pull/248

[guillemj]

LGTM to removing changes to upstream .gitignore, but maybe we can remove the custom builddirectory too?

From the commit reverting the previous change:

While the general idea makes sense and would make things better, this
had some push back on the review and still got merged anyway. It also
conflicts with an old proposal that still is pending to be updated
and re-proposed to try to unify the build paths for all packages at the
dpkg and debhelper layer, via a new dpkg-build-api level. And doing a
migration twice seems wasteful.

Ref: https://lists.debian.org/debian-dpkg/2020/03/msg00003.html

So, I agree with the idea of the change, but probably not in this specific form.

[ottok]

In summary, the proposal from 2020 in https://lists.debian.org/debian-dpkg/2020/03/msg00003.html is instead of all these and more:

  - debian/files
  - debian/*substvars
  - debian/<binary-pkgname>/
  - debian/*debhelper.log
  - debian/.debhelper/
  - debian/tmp/

..just have this:

  - debian/.build/

with all artifacts there.

This would certainly help keep the debian/* stuff tidy and help people learning Debian packaging understand clearly what is a build artifact and what is not. However since this hasn't moved since 2020 I am not sure if it makes sense to postpone tidying things up in Go debian/rules while waiting.

[ottok]

Rebased on latest master