the gnat-13 transition is completed

[Nicolas Boulenguez <nicolas@debian.org>]

Hello.

GCC-13 is now the default Ada compiler for the unreleased ("testing")
Debian 13 ("trixie") distribution.

This list describes some changes specific to Debian.

* The GNU C library enables 64 bits durations on 32 bits architectures
  like arm{el,hf}, preventing an overflow in 2038.  The implementation
  of the Ada run time library has required significative changes,
  currently reviewed by the GCC maintainers.

  Ada sources interfacing with the C time_t, timeval or timespec types via
    non-standard parts of Ada.Calendar,
    GNAT or System units
  will probably require adjustements for
    /usr/lib/gcc/*/13/adainclude/s-c_time.ads.

  For people interfacing directly, here is a description of the issues
  encoutered with libgnat, and a list of affected C functions.
  https://sourceware.org/glibc/wiki/Y2038ProofnessDesign
  https://gcc.gnu.org/pipermail/gcc-patches/2024-May/650717.html.

* As a prerequisite for installability of non-default gnat versions
  alongside the default one, the "gnatgcc" symbolic link emits a
  deprecation warning. It will be removed in gnat-14.

  The warning explains how to replace it.
  Packagers using /usr/share/ada/packaging.mk won’t notice.

* The former ALI version in -dev package names is replaced with a
  generated virtual package, preventing a common source of packaging
  errors and simplifying transitions without ABI change.

  Libraries install their documentation to /usr/share/doc/lib*-dev/
  whether or not they provide it in a separate -doc package (in the
  absence of other reasons, see libxmlada-*).
  Programmers browising local documentation with dwww, dhelp, dochelp,
  doc-central or similar won’t notice.

Thanks to everyone involved for the six last months.