bug#58509: 29.0.50; Synchronous nativecomp

[Lars Ingebrigtsen <larsi@gnus.org>]

Andrea Corallo <akrl@sdf.org> writes:

> to get practical I think what Lars'd like to have is: at the end of
> 'maybe_swap_for_eln', in case the .eln is not found, a syncronous
> invocation of the native compiler to produce and use the .eln file
> (indeed only when this flag is used).
>
> In principal as decribed it should be relatively easy, the only
> technical caveat I can think of now are potential circular dependecies
> generated by loading comp.el.

It's kinda the same problem as with the infinite recursion problem with
the trampolines, so perhaps this could have the same solution?  I.e., in
the Emacs that we fork to do the nativecomp, we should switch off both
JIT and trampoline generation?  (We'd need to add such a mechanism, of
course.)

> The comment I have is that we could have this mode capable of being used
> also in interactive sessions, in case I think we should really think of
> a better name for the flag, something like --native-compile-sync?  Or
> anyway something that highlights the "synchronousness" of the enabled
> mechanism.

Yes, that's a better name for the switch.