Fix regex.hh compilation
Fix regex.hh compilation

Repeat after me: I will not blindly push commits that I havent
compiled.

Fixes #990

mawww/kakoune,ekie/kakoune,occivink/kakoune,lenormf/kakoune,alexherbo2/kakoune,danr/kakoune,lenormf/kakoune,danr/kakoune,Somasis/kakoune,jkonecny12/kakoune,casimir/kakoune,mawww/kakoune,danr/kakoune,casimir/kakoune,jkonecny12/kakoune,ekie/kakoune,flavius/kakoune,jjthrash/kakoune,jjthrash/kakoune,ekie/kakoune,occivink/kakoune,Somasis/kakoune,jjthrash/kakoune,lenormf/kakoune,alexherbo2/kakoune,flavius/kakoune,jkonecny12/kakoune,flavius/kakoune,occivink/kakoune,mawww/kakoune,occivink/kakoune,casimir/kakoune,mawww/kakoune,Somasis/kakoune,alexherbo2/kakoune,Somasis/kakoune,flavius/kakoune,alexherbo2/kakoune,casimir/kakoune,jkonecny12/kakoune,jjthrash/kakoune,ekie/kakoune,lenormf/kakoune,danr/kakoune