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

[Jorn Vernee]

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

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Commit messages:
 - Print option errors

Changes: https://git.openjdk.java.net/panama-foreign/pull/500/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=500&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265211
  Stats: 15 lines in 1 file changed: 13 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/500.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/500/head:pull/500

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