run-tests: revert "EXTENSIONS" section bug introduced in #2673

[maaarghk]

documented behaviour of loading extensions from shared modules was
broken some time ago, this patch reintroduces that feature whilst
retaining other changes which allow the skip cache to work

rationale is in #2673 (comment)

the output of skipcache __destroy is the same before and after this patch, so I am confident it doesn't break anything.

[nikic]

I'm not sure this is really right either. For php-src itself, you do want to get all extensions from modules/.

[maaarghk]

I think that's fine, because loaded is calculated using the parameters which are passed from the Makefile, it won't add any extension= or zend_extension= lines for anything that the Makefile is processing.

[nikic]

And this is why I always call run-tests.php directly -- too much magic in make test...

I think the behavior of run-tests.php itself is correct here. It wouldn't make much sense if you called run-tests.php -d extension_dir=DIR and that would simply get ignored.

We should address this on the side of make test. I think a good way to do so would be to make it not set extension_dir at all (leave it at the default), and instead pass in -d extension= using absolute rather than relative paths.

[nikic]

I've put up #6983 for the variant described above. Can you tell me whether that would work for your use-case?