[xpressive] Accept one line pull that's been outstanding for a couple years?

From: Brian Kuhl (kuhlenough_at_[hidden])
Date: 2019-11-21 20:25:09

Hi Boost,
We've been running nightly regression on this for years now at Wind River
over a couple Boost releases. Any reason it can't be merged?

https://github.com/boostorg/xpressive/pull/5

Thanks

Brian