build: Move xdgmime to a meson subproject
This means:
- It’s always available, so the tests no longer have to be optional
- It gets bundled in release tarballs so the above is always true
- The
meson setup
andmeson build
commands will automatically update it if needed - It gets built using meson, rather than autotools, so the old GNU make build system in xdgmime can be dropped (see xdgmime#36 (closed))
- The
xdgmime-path
meson option is no longer needed and has been dropped
Signed-off-by: Philip Withnall pwithnall@gnome.org