meson: autodetect split-usr

Also move the status from "features" to the paths section. This is more of an
anti-feature.

meson.build

@@ -54,7 +54,11 @@ endif
 
 #####################################################################
 
-split_usr = get_option('split-usr')
+if get_option('split-usr') == 'auto'
+        split_usr = run_command('test', '-L', '/bin').returncode() != 0
+else
+        split_usr = get_option('split-usr') == 'true'
+endif
 conf.set10('HAVE_SPLIT_USR', split_usr)
 
 rootprefixdir = get_option('rootprefix')
@@ -2738,6 +2742,7 @@ run_target(
 status = [
         '@0@ @1@'.format(meson.project_name(), meson.project_version()),
 
+        'split /usr:                        @0@'.format(split_usr),
         'prefix directory:                  @0@'.format(prefixdir),
         'rootprefix directory:              @0@'.format(rootprefixdir),
         'sysconf directory:                 @0@'.format(sysconfdir),
@@ -2874,7 +2879,6 @@ foreach tuple : [
         ['man pages',        want_man],
         ['html pages',       want_html],
         ['man page indices', want_man and have_lxml],
-        ['split /usr',       conf.get('HAVE_SPLIT_USR') == 1],
         ['SysV compat'],
         ['utmp'],
         ['ldconfig'],

meson_options.txt

@@ -16,8 +16,8 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with systemd; If not, see <http://www.gnu.org/licenses/>.
 
-option('split-usr', type : 'boolean', value : false,
-       description : '''assume that /bin, /sbin aren't symlinks into /usr''')
+option('split-usr', type : 'combo', choices : ['auto', 'true', 'false'],
+       description : '''/bin, /sbin aren't symlinks into /usr''')
 option('rootlibdir', type : 'string',
        description : '''[/usr]/lib/x86_64-linux-gnu or such''')
 option('rootprefix', type : 'string',