[PATCH] Deprecate use of stdio

The following patches are aimed at deprecating the use of stdio by the script lexer in PHP 4, because certain stdio libraries impose restrictive limits on the number of open handles*. The patches have been split functionally for the benefit of the reviewer. Patch 1 adds a stream interface which fills in a zend_file_handle. This is simply a modified copy of the open_as_file function. Patch 2 adds zend_open() which expects the implementation to fill in a zend_file_handle. Patch 3 makes PHP supply a zend_open implementation. Patch 4 modifies the lexer skeleton so that it can read using POSIX functions and stdio. It also makes open_file_for_scanning use zend_open. * Background: Even the most modern Solaris ships with a stdio library which cannot handle fds over 255. This severely limits any web server which may open more than 255 fds per process, because it won't be able to parse PHP scripts anymore. I've evaluated integrating sfio into the build process, but as it turns out, a full and complete integration would be a lot more complex than addressing the issue up-front. - Sascha