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')
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<tr><td><span title='2024-12-03 08:42:52 +0100'>2024-12-03</span></td><td><a href='/guix/commit/gnu/packages/m4.scm?id=178c3115c47905f4ddad2740ada2725db42ed478'>gnu: m4: Fix build of tests on the 64bit Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/m4.scm (m4)[arguments]: When building on the 64bit Hurd,
add CFLAGS to #:configure-flags.

Change-Id: Iab16194f4cd2911b4610dddd855064ddc4958dd9
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2024-12-03 08:39:00 +0100'>2024-12-03</span></td><td><a href='/guix/commit/gnu/packages/m4.scm?id=493e07bd000dcf56a565088f0f4ab757fa67f328'>gnu: m4: Fix build for the 64bit Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/base.scm (grep)[arguments]: When building for the 64bit Hurd,
add patch-sigsegv.h stage.

Change-Id: I82993ebde268867348893556a9476faa5c4e9453
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>