Enable `files` provider
This MR fixes https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1041438
In a nutshell, upstream SSSD deprecated the option id_provider = files
, which should be automatically enabled when using
enable_files_domain = True
. This option is still needed in order to
support smartcard authentication of local users, which is what the
gdm3 package tests in its dep8 test. For now, the recommended
workaround is to build SSSD using --with-files-provider
, which is
what this MR does.
According to upstream, SSSD 2.10 should support smartcard local auth
via id_provider = proxy
, which will allow us to stop using
--with-files-provider
if needed.