Don't install systemd units unless using libsystemd session tracking.

Submitted upstream:

  https://gitlab.freedesktop.org/polkit/polkit/-/merge_requests/134

diff --git a/data/meson.build b/data/meson.build
--- a/data/meson.build
+++ b/data/meson.build
@@ -26,7 +26,7 @@ if enable_pam
   )
 endif
 
-if enable_logind
+if session_tracking == 'libsystemd-login'
   configure_file(
     input: 'polkit.service.in',
     output: '@BASENAME@',
diff --git a/meson.build b/meson.build
--- a/meson.build
+++ b/meson.build
@@ -199,7 +199,7 @@ if enable_logind
 
   # systemd unit / service files
   systemd_systemdsystemunitdir = get_option('systemdsystemunitdir')
-  if systemd_systemdsystemunitdir == ''
+  if systemd_systemdsystemunitdir == '' and session_tracking == 'libsystemd-login'
     systemd_dep = dependency('systemd', not_found_message: 'systemd required but not found, please provide a valid systemd user unit dir or disable it')
     # FIXME: systemd.pc file does not use variables with relative paths, so `define_variable` cannot be used
     systemd_systemdsystemunitdir = systemd_dep.get_pkgconfig_variable('systemdsystemunitdir')
mmary</a><a href='/guix/refs/?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>refs</a><a class='active' href='/guix/log/gnu/packages/cyrus-sasl.scm?showmsg=1'>log</a><a href='/guix/tree/gnu/packages/cyrus-sasl.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>tree</a><a href='/guix/commit/gnu/packages/cyrus-sasl.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>commit</a><a href='/guix/diff/gnu/packages/cyrus-sasl.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/cyrus-sasl.scm'>
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<div class='path'>path: <a href='/guix/log/?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d&amp;showmsg=1'>root</a>/<a href='/guix/log/gnu?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d&amp;showmsg=1'>gnu</a>/<a href='/guix/log/gnu/packages?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d&amp;showmsg=1'>packages</a>/<a href='/guix/log/gnu/packages/cyrus-sasl.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d&amp;showmsg=1'>cyrus-sasl.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/cyrus-sasl.scm?id=f8953bea858f894b406eed4a0aca0cd4c4d8671d'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2021-03-10 11:51:09 +0100'>2021-03-10</span></td><td class='logsubject'><a href='/guix/commit/gnu/packages/cyrus-sasl.scm?id=70128b8afacf332b0aff69ebcad6868fd158e8ad'>gnu: cyrus-sasl: Fix CVE-2019-19906.</a></td><td>Léo Le Bouter</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/packages/patches/cyrus-sasl-CVE-2019-19906.patch: New patch.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/cyrus-sasl.scm (cyrus-sasl/fixed): New variable. Apply patch.
(cyrus-sasl)[replacement]: Graft.


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