[php-src] Issue #14792: Compilation failure on pdo_mysql extension for 8.4alpha Docker image

Issue: https://github.com/php/php-src/issues/14792 Author: jnoordsij ### Description After tagging of the first alpha for 8.4 occurred yesterday, I proceeded to provide an upstream PR to the official Docker image repository: https://github.com/docker-library/php/pull/1526. However the test for the builds fail when attempting to compile the pdo_mysql extension, which can be reproduced as follows (see also https://github.com/docker-library/php/pull/1526#issuecomment-2204458471): ``` docker buildx build --pull https://github.com/docker-library/php.git#refs/pull/1526/head:8.4-rc/bookworm/cli --tag php:8.4-rc docker run -it --rm php:8.4-rc docker-php-ext-install pdo_mysql ``` Possibly related commits are https://github.com/php/php-src/commit/11accb5cdff7977388fb604698fc7133f6491c0a and https://github.com/php/php-src/commit/715b9aaa09e1ad76a94f32b17da7927592fdae0a, which may require a change in the upstream configuration? Note: given that there's no official announcement for this alpha release yet and this is thus an overly eager attempt from my side, this might be a known issue that will be resolved before the announcement; if so, feel free to close! ### PHP Version PHP 8.4.0alpha1 (cli) (built: Jul 3 2024 14:16:13) (NTS) (unreleased) ### Operating System Debian bookworm