Windows installer: add winpaths.py to extend %PATH% so that build find msys2 binaries including Make.
# Snap distribution
main_target: Snap
tar_opts=--absolute-names --exclude=.hg --exclude=.git --exclude=.*.pyc --exclude=.*.swp
Snap: snap_built
snap_built: all_sources revisions.txt
tar -C $(src) $(tar_opts) -c snap | tar -C sources -x
cp revisions.txt sources
cd sources; snapcraft --debug
touch $@