bug#60996: 29.0.60; Native compile fails to remove temp file for trampoline

[Eli Zaretskii]

> Cc: 60996@debbugs.gnu.org
> Date: Sun, 29 Jan 2023 09:01:16 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> and leave the rest to the user: if they want the trampolines to
> be compiled, but not written to eln-cache, let them tweak
> native-comp-eln-load-path to direct trampolines to another place,
> whether the temporary directory or any other directory.

Alternatively, we could modify comp-enable-subr-trampolines to be able
to have a string value, which would then be a directory to which to
write the trampolines.