build.sh: add CHROOT_MODE to support unshare
based on a rough draft by Matthias Geiger werdahias@riseup.net
Signed-off-by: Fabian Grünbichler git@fabian.gruenbichler.email
based on a rough draft by Matthias Geiger werdahias@riseup.net
Signed-off-by: Fabian Grünbichler git@fabian.gruenbichler.email