bug#55811: 29.0.50; No flymake diagnostics for no-byte-compile files

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> I stumbled onto a related thing earlier tonight -- I said `M-x
> byte-compile-file RET RET' and then it did nothing -- because of the
> no-byte-compile.
>
> I'm not sure whether I agree with that -- if I've explicitly asked Emacs
> to do it, I think that should override the cookie.  Or at least issue a
> message of some sort.

That's a slightly different case from mine: the `no-byte-compile` is
often used either because the user really only ever wants to load the
`.el` or because the compilation is known to fail (e.g. because it
requires macros defined in a package that's not marked as a strict
dependency, very common in tests).

Generating a `.elc` file explicitly with `M-x byte-compile-file` could
be a problem if subsequent "normal" use will fail to update that `.elc`
because of the `no-byte-compile`.

So, I think `byte-compile-file` should not silently override the
`no-byte-compile`.  It could prompt to choose between "really compile"
and "compile but don't generate the .elc file".


        Stefan