Some PECLs depend on other PECLs and, like internal PHP extension
dependencies, need to be loaded in the correct order. This makes this
possible by adding the argument "peclDeps" to buildPecl, which adds
the extension to buildInputs and is treated the same way as
internalDeps when the extension config is generated.

Fix an issue brought up in #86463, where the apcu_bc extension isn't
loaded correctly since it produces a .so with a different name than
the extension name. Also, the apcu extension has to be loaded and
loaded prior to loading this extension.

The pcs extension fails to load at runtime with PHP 7.3, so let's mark
it broken from 7.3 onwards. It also depends on the tokenizer internal
extension.

The couchbase extension depends on the igbinary PECL which needs to be
loaded and loaded prior to it. It also seems like the pcs extension
isn't actually needed - it at least builds and loads without it. Since
the pcs extension dependency was the reason couchbase didn't build on
PHP 7.4 it now does, so let's unmark it broken.

php.buildPecl: Make it possible for PECLs to depend on other PECLs, fix apcu_bc and couchbase