RFR: 7903837: apidiff: build.sh issues on Windows [v2]

[Christian Stein]

On Wed, 25 Sep 2024 19:21:20 GMT, Jonathan Gibbons <jjg at openjdk.org> wrote:

>> Please review some `build.sh` and `Makefile` changes to address issues building on Windows.
>> 
>> The primary Windows issue was missing use of `mixed_path` when passing some filenames into `make`.
>> There is some additional cleanup (for all platforms) to normalize the `DEPS_DIR` and add missing items to the `sanity` and `check_build_vars` targets.
>> 
>> This has been tested on macOS. Can someone with access to a Windows machine test it on Windows, please?
>
> Jonathan Gibbons has updated the pull request incrementally with one additional commit since the last revision:
> 
>   address review feedback

https://github.com/openjdk/apidiff/blob/a10e1426e21978b522d93e1406731240197c2d37/test/junit/JUnitTests.gmk#L33 also needs some extra care to not pass an empty `$(DAISYDIFF_JAR)` element.

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Changes requested by cstein (Committer).

PR Review: https://git.openjdk.org/apidiff/pull/12#pullrequestreview-2329364618