Document spkg-configure.m4 and distros directory

[jhpalmieri]

For Sage packages, the spkg-configure.m4 script and the distros directory don't seem to be documented. Remedy this.

Part of #27330 Meta-ticket: spkg-configure: Try to use as many system packages as possible

Component: documentation

Author: John Palmieri

Branch/Commit: e9e8a23

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/30543

[jhpalmieri]

Branch: u/jhpalmieri/document-spkg-configure.m4

[jhpalmieri]

comment:2

I'm happy to hear suggestions for the wording and the descriptions of these components of Sage packaging.

---

New commits:

90df5d6

trac 30543: document build/pkg/PACKAGE/spkg-configure.m4 and .../distros

[jhpalmieri]

Commit: 90df5d6

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

6a63edf

trac 30543: document build/pkg/PACKAGE/spkg-configure.m4 and .../distros

[sagetrac-git]

Changed commit from 90df5d6 to 6a63edf

[mkoeppe]

comment:4

There is some material in https://doc.sagemath.org/html/en/developer/portability_testing.html#using-sage-s-database-of-equivalent-distribution-packages that the new documentation should link to

[mkoeppe]

comment:5

See also #26668, #29018

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

e9e8a23

trac 30543: more documentation

[sagetrac-git]

Changed commit from 6a63edf to e9e8a23

[jhpalmieri]

comment:8

Here are some additions.

[mkoeppe]

Reviewer: Matthias Koeppe

[mkoeppe]

comment:9

LGTM.

[vbraun]

Changed branch from u/jhpalmieri/document-spkg-configure.m4 to e9e8a23