quasicomputational authored Apr 25, 2018 and Mikhail Glushenkov committed May 08, 2018

These are inspired by a plan described in a comment in #2522, and only
implement a quite limited form of recursive matching: only a single **
wildcard is accepted, it must be the final directory, and, if a **
wildcard is present, the file name must include a wildcard.

Or-patterns are not implemented, for simplicity.

Closes #3178, #2030.