RFR: 7903132: Replace casts with type test pattern

[Ethan McCue]

On Fri, 25 Mar 2022 15:54:08 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> (I was counting on some CI/CD to be triggered on PR, which i suppose either isn't the case or isn't the case unless i get past the issue number check)
>
> Questions can be directed at the mailing list (either jextract-dev at openjdk.java.net or panama-dev at openjdk.java.net). You can send an email there without making an account as well (it will go through a moderation queue first).
> 
> I agree the error message is not great. In this case the issue seems to be this line in build.gradle:
> 
> 
> def clang_version = new File("${libclang_home}/lib/clang/").list()[0]
> 
> 
> i.e. the `libclang_home` directory does not have the expected directory structure. It is looking for a directory like `<libclang_home>/lib/clang/<VERSION>`. So please make sure that exists.

On a stock mac install with XCode it ended up being located at `/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/` - in case that is of use to anyone.

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PR: https://git.openjdk.java.net/jextract/pull/5