maintainer-strict-api - A tool to check and enforce encapsulation

Hi, following Joe Watkins' suggestion, I'm reviving a PR I had proposed for 7.0. The PR was abandoned because it was coming too late to target 7.0. The PR is available at : https://github.com/php/php-src/pull/1508 It is introducing a new configure flag. When this flag is set, non-compliant access to the zval and zend_string struct elements trigger compile-time failures, making it an API compliance check tool. You will find more details in the PR. Please give thoughts. Regards François