Release 2.40 doesn't build with GCC 15

[Yury Khrustalev]

Hi,

Glibc release release/2.40/master does not build with GCC 15 giving
multiple errors in timezone/ folder, for example:

  zdump.c:92:66: error: standard ‘reproducible’ attribute can only be
  applied to function declarators or type specifiers with function type
     92 | ATTRIBUTE_REPRODUCIBLE static intmax_t delta(struct tm *, struct tm *);
        |                                                                  ^~
  zdump.c:92:66: note: did you mean to specify it after ‘)’ following function
  parameters?

It looks like GCC 15 wants the ATTRIBUTE_REPRODUCIBLE attribute to be
after function declaration rather than before.

Does this mean that there is maximum GCC version for each Glibc release
that is supposed to work? If so, is there a place where preferable GCC
versions are documented for each Glibc release? It would help to know
this when I backport changes to older releases and need to test them.

Thanks,
Yury