configure: update to and require use of autoconf 2.72

[nilason]

Follow up to the de facto update with commit: ec42cfa.

Run with autoreconf -vfi.

(What version we use is only of importance for developers updating the configure scripts, not users/builders which use the generated configure script anyway.)

[marisn]

Do we have to bump up autoconf requirement? The fact that configure was generated with a more recent version doesn't mean an older version can not be used.

[nilason]

Do we have to bump up autoconf requirement? The fact that configure was generated with a more recent version doesn't mean an older version can not be used.

We don’t have to, but using different versions lead to unrelated changes (cluttered history). The version is only of importance for us devs, as it now stands, so whichever is more convenient.

[ninsbl]

Since you are modifying the build system: Did you notice that current builds show up with Large File Support (LFS): no? See e.g.: https://github.com/OSGeo/grass/actions/runs/18658480388/job/53193250341#step:10:275
Here: https://github.com/OSGeo/grass/actions/runs/18549653323/job/52874607114 it was stil enabled by default... Is that a regression that warrants a new issue?

[marisn]

Since you are modifying the build system: Did you notice that current builds show up with Large File Support (LFS): no? See e.g.: https://github.com/OSGeo/grass/actions/runs/18658480388/job/53193250341#step:10:275 Here: https://github.com/OSGeo/grass/actions/runs/18549653323/job/52874607114 it was stil enabled by default... Is that a regression that warrants a new issue?

Yes, that is a regression. LFS detection works, but reporting – doesn't. Here's a PR with the fix: #6537

[marisn]

We don’t have to, but using different versions lead to unrelated changes (cluttered history). The version is only of importance for us devs, as it now stands, so whichever is more convenient.

I was more thinking of downstream packagers as on some distros they discard our shipped configure file and generate their own. Now they will be forced to use 2.72, though 2.71 should work just fine as they don't contribute back their configure files. But probably it doesn't matter that much.