php/php-src — pull request #13 by mytskine (2012-03-20 12:17:05+00:00)
Title: Fix bug #40531 mb_substr optional parameters

The fix is in 3 commits. First, I enable a test that was skipped. Then I add a small feature to `zend_verify_arg_type()`. The last commit modifies the 2 functions that were buggy, `mb_substr()` and `mb_strcut()`. The last commit message details the changes.

I based my work on the branch PHP-5.4, but maybe this fix should be applied to an older version.