[RFC] add regenerate Makefile target

[Simon Marchi]

On 3/18/24 13:28, Christophe Lyon via Gdb wrote:
> I'm not up-to-date with gdb's policy about patches: are they supposed
> to be posted with or without the regenerated parts included?
> IIUC they are not included in patch submissions for binutils and gcc,
> which makes the pre-commit CI miss some patches.

We post the patches with the regenerated parts.

Simon