-Dsasl requires explicit -Ddriver_remote=enabled (the default)

Software environment

• Operating system: OS independent (reported on GNU Guix)
• libvirt version: 7.5.0

Description of problem

According to TingPing in the #mesonbuild support channel, https://gitlab.com/libvirt/libvirt/-/blob/master/meson.build#L1175 should not use .enabled() to check for remote driver support here, given that it won't correctly match .auto().

I can't say what it should use, but they've promised to respond with a better description if I filed this issue :-) Thanks TingPing!

Steps to reproduce

1. Build libvirt with ‘-Dsasl=enabled’ but without an explicit ‘-Ddriver_remote=enabled’
2. The build reports ‘sasl: NO’ despite reporting ‘Remote: YES’ above.