[foreign-jextract] RFR: 8265211: Print specific error message when an option parsing error occurs

[Maurizio Cimadamore]

On Wed, 14 Apr 2021 11:37:18 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Hi,
> 
> This patch makes jextract print a more specific error message when an option parsing error occurs, where currently only the help message is printed.
> 
> For instance, when using an unrecognized option `-o` it will print
> 
> 
> OPTION ERROR: o is not a recognized option
> 
> 
> Or when specifying multiple header files
> 
> 
> OPTION ERROR: Expected 1 header file, not 3
> 
> 
> Thanks,
> Jorn

As discussed offline, might be helpful to print help from `printOptonError` anyway.

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Marked as reviewed by mcimadamore (Committer).

PR: https://git.openjdk.java.net/panama-foreign/pull/500