[PATCH v5 00/12] PR ld/24600: Add general linker support for mapless archives

[Maciej W. Rozycki]

Hi,

 This is v5 of a patch series to add linker support for mapless archives 
and `--start-lib'/`--end-lib' command line options, rebased on top of 
commit d75f191dc631 ("PR 33821 use after free commit e6357caf7579") and 
the 2.46 version bump, and also addressing further feedback received for 
v3 since v4 has been posted.

 Here's an overview of the updated set yet outstanding:

 1. Unset the format on releasing a BFD's objalloc memory.

 2. Sanitize back end flavour for external symbols retrieval with aout
    BFDs.

 3. Correct archive format determination for non-default link emulations.

 4. Make the file position consistently unsigned in symbol maps.

 5. Add a BFD pointer member to `struct carsym' (symbol map).

 6. Expand support for mapless archives across all the BFD linkers (beyond 
    just XCOFF).

 7. Add `--link-mapless'/`--no-link-mapless' LD options to control the new 
    feature, on by default (and now switchable off for XCOFF too, but not 
    effective for Alpha/VMS whose archive format does not support omitting 
    an index).

 8. Guard NULL pointer use with assertions in LD where adding a new input
    file.

 9. Factor out input file insertion in LD.

10. Add a BFD pointer member to structures referring to archive members.

11. Add fake archive support to BFD as a list of member BFDs supplied.

12. Add `--start-lib'/`--end-lib' LD options and a corresponding linker 
    script feature building upon the fake archive BFD feature.

See individual change descriptions for details.

 This has been verified across 250 targets, causing no regressions and 
adding no failures in new tests.

 OK to apply?

Previous iterations:

- v4 at: <https://inbox.sourceware.org/binutils/alpine.DEB.2.21.2601061929190.45251@angie.orcam.me.uk/>.

- v3 at: <https://inbox.sourceware.org/binutils/alpine.DEB.2.21.2511191836470.57987@angie.orcam.me.uk/>.

- v2 at: <https://inbox.sourceware.org/binutils/alpine.DEB.2.21.2511050716450.25436@angie.orcam.me.uk/>.

- v1 at: <https://inbox.sourceware.org/binutils/alpine.DEB.2.21.2509251408330.15999@angie.orcam.me.uk/>.  

  Maciej