RFR: 8348586: Optionally silence make warnings about non-control variables

[Maurizio Cimadamore]

On Fri, 24 Jan 2025 17:08:42 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> When you set a variable on the make command line that is not a known control variable, make emits a note like this:
> 
> 
> Note: Command line contains non-control variables:
> * MODULES=
> * IDEA_OUTPUT=/mnt/h/openjdk/git-jdk2/.idea
> Make sure it is not mistyped, and that you intend to override this variable.
> 'make help' will list known control variables.
> 
> 
> Since [JDK-8347825](https://bugs.openjdk.org/browse/JDK-8347825), this happens whenever you run idea.sh, and it is confusing to users.
> 
> I introduce a general way of silencing such complaints using the new control variable `ALLOW`, and start by applying it on the idea.sh script.

Marked as reviewed by mcimadamore (Reviewer).

Works fine here - thanks!

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PR Review: https://git.openjdk.org/jdk/pull/23302#pullrequestreview-2573207502
PR Comment: https://git.openjdk.org/jdk/pull/23302#issuecomment-2613031727