This reverts commit f09ab88891, reversing
changes made to effc761e0e.
This is being temporarily reverted to make it easier to release an
urgent fix for v10.15.1.
This PR adds `snaps` under Flask build flags to the extension. This branch is mostly equivalent to the current production version of Flask, excepting some bug fixes and tweaks.
Closes#11626
Dan Miller
Mark Stacey
Frederik Bolding
Erik Marks