RFR: 8344318: Enhance configure help for enabling/disabling single JVM features

[Erik Joelsson]

On Fri, 22 Nov 2024 09:10:40 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> Probably it is better to mention the disable syntax.
>> `$PRINTF "The flag --disable-jvm-feature-<name> can be used to disable a single JVM feature.\n"`
>> That is also a bit shorter.
>
> We could maybe move the info to the start of the 'Optional Features:' section if you prefer this. Would be more general.
> But is it really true that for all optional features the enable/disable syntax works ?

For any `--enable-<foo>` flag autoconf generates a corresponding `--disable-<foo>` flag. Using `--enable-<foo>` is equivalent to `--enable-<foo>=yes` and using `--disable-<foo>` is equivalent to `--enable-<foo>=no`. It's encouraged (from autoconf) to have "enable/disable" flags only take those values, but technically, you could supply any value to them. 

We try to use `--with-<foo>` for parameters that expect different arguments and those are usually possible to turn off as well using `--without-<foo>`, which is equivalent to `--with-<foo>=no`. I don't think we have properly implemented support for every `--without-<foo>` in our configure script however.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22231#discussion_r1853955027