- Use emalloc/efree for internal allocations so bsdiff respects memory_limit and is visible to PHP's memory tracking.
- Replace POSIX file I/O with PHP streams and consolidate cleanup.
- Explicit binary-mode flag ("wb"/"rb") for diff files, fixing potential corruption on Windows.
- Improve BZip2 auto-detection in config.m4.
- Add PHP 8.3, 8.4, and 8.5 to CI matrix.