RFR: 7903134: Imrpove error reporting in jextract gradle build

Fri Mar 25 17:17:09 UTC 2022

On Fri, 25 Mar 2022 16:16:37 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Improve error reporting around missing LLVM paths in jextract gradle build.
> 
> This patch tries to detect missing paths and throw a descriptive error, instead of a more cryptic one.
> 
> I've also added the `.idea` folder to the `.gitignore` file.

Looks good - should we take the change and also rename libclang_home to llvm_home?

-------------

PR: https://git.openjdk.java.net/jextract/pull/8