PHP 5.3.7 compatibility

It looks like the markdown filter is not compatible with 5.3.7.
All our websites stopped displaying content written with the markdown filter because of PHP errors with preg_replace_callback() function in markdown.php, from the moment the PHP version has been upgraded from 5.3.6 to 5.3.7

The following errors are saved in the reports:
preg_replace_callback(): Compilation failed: POSIX collating elements are not supported at offset 116 in .../contrib/markdown/markdown.php on line 998.
preg_replace_callback(): Compilation failed: POSIX collating elements are not supported at offset 163 in .../contrib/markdown/markdown.php on line 1005.

The faulty lines of code (998 and 1005):

			if ($this->list_level) {
				$text = preg_replace_callback('{
						^
						'.$whole_list_re.'
					}mx',
					array(&$this, '_doLists_callback'), $text);
			}
			else {
				$text = preg_replace_callback('{
						(?:(?<=\n)\n|\A\n?) # Must eat the newline
						'.$whole_list_re.'
					}mx',
					array(&$this, '_doLists_callback'), $text);
			}

Has anybody experienced that ? This is critical as any of your websites using markdown (the filter itself not particularly this module) won't display their content anymore.