This moves yet more extensions from the base build to
phpPackages.ext. Some of the extensions are a bit quirky and need
patching for this to work, most notably mysqlnd and opcache.
Two new parameters are introduced for mkExtension - internalDeps and
postPhpize. internalDeps is used to specify which other internal
extensions the current extension depends on, in order to provide them
at build time. postPhpize is for when patches and quirks need to be
applied after running phpize.
Patch notes:
- For opcache, older versions of PHP have a bug where header files are
included in the wrong order.
- For mysqlnd, the config.h is never included, so we include it in the
main header file, mysqlnd.h. Also, the configure script doesn't add
the necessary library link flags, so we add them to the variable
configure should have added them to.