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

[Eli Zaretskii <eliz@gnu.org>]

> From: Andy Moreton <andrewjmoreton@gmail.com>
> Date: Sat, 28 Jan 2023 21:15:02 +0000
> 
> I know Eli is not a fan of inhibit-automatic-native-compilation, but I
> think there is a place for it. Users may want to use precompiled .eln
> files but not waste effort on native compiling other code.
> 
> If this error can be suppressed such that the only effect is for a temp
> file to be left around, that is a reasonable solution to this.

What I dislike is that inhibit-automatic-native-compilation promises
not to start compilation, but it actually does start compilation, for
trampolines, and writes them to a directory we invent behind user's
back.  What I'd like to do is to go to the previous situation, where
compilation of trampolines was disabled at startup if
native-compilation is not available (something that happens on Windows
only), 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.