[PATCH 0 of 2] re2 for check-code, working around missing finditer

[Simon Heimberg]

There are two implementations of re2

Facebooks implementation does not have finditer
 https://github.com/facebook/pyre2/blob/master/README.rst#missing-features
But the one from axiak does
 https://github.com/axiak/pyre2/blob/master/src/re2.pyx#L513