meson: emit a warning if rootprefix is set

It's printed at the end because it's the easiest to spot there.

When meson is upgraded to 0.43.1, we'll be able to use warning() instead.

diff --git a/meson.build b/meson.build
index 052474895d532bb7cff456bd3c22df0b9e4d5079..376c8b84be6baa3e1ec6c2094d6b810e68f156ee 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -54,14 +54,15 @@ endif
 
 #####################################################################
 
+split_usr = get_option('split-usr')
+conf.set10('HAVE_SPLIT_USR', split_usr)
+
 rootprefixdir = get_option('rootprefix')
-conf.set10('HAVE_SPLIT_USR', get_option('split-usr'))
 # Unusual rootprefixdir values are used by some distros
 # (see https://github.com/systemd/systemd/pull/7461).
-if get_option('split-usr')
-        rootprefixdir = rootprefixdir != '' ? rootprefixdir : '/'
-else
-        rootprefixdir = rootprefixdir != '' ? rootprefixdir : '/usr'
+rootprefix_default = get_option('split-usr') ? '/' : '/usr'
+if rootprefixdir == ''
+        rootprefixdir = rootprefix_default
 endif
 
 sysvinit_path = get_option('sysvinit-path')
@@ -2615,3 +2616,10 @@ status += [
         'disabled features: @0@'.format(', '.join(missing)),
         '']
 message('\n         '.join(status))
+
+if rootprefixdir != rootprefix_default
+        message('WARNING:\n' +
+                '        Note that the installation prefix was changed to "@0@".\n'.format(rootprefixdir) +
+                '        systemd used fixed names for unit file directories and other paths, so anything\n' +
+                '        except the default ("@0@") is strongly discouraged.'.format(rootprefix_default))
+endif