Patch for version_compare() to fix bug #21611

Hello, Attached is a patch that makes version_compare() treat versions such as 4.0.1p1 like 4.0.1pl1. I know this version suffix isn't used by PHP, but there were some problems because PEAR packages used it, and i don't see any problem with version_compare() handling non-php versions as well. (Afaik, the "alpha" and "beta" suffixes are also not used, but they are in version_compare).