--- monitoring-plugins-2.3.3.old/configure.ac	2023-02-01 14:40:55.000000000 +0100
+++ monitoring-plugins-2.3.3/configure.ac	2023-06-15 16:21:19.637049416 +0200
@@ -328,6 +328,25 @@
   LIBS="$_SAVEDLIBS"
 ])
 
+
+AC_ARG_WITH([systemd], [AS_HELP_STRING([--without-systemd], [Skips systemd support])])
+
+dnl Check for libsystemd
+AS_IF([test "x$with_systemd" != "xno"], [
+  _SAVEDLIBS="$LIBS"
+  AC_CHECK_LIB(systemd,sd_get_sessions,,,-lsystemd)
+  if test "$ac_cv_lib_systemd_sd_get_sessions" = "yes"; then
+    SYSTEMDLIBS="-lsystemd"
+    SYSTEMDINCLUDE=""
+    AC_SUBST(SYSTEMDLIBS)
+    AC_SUBST(SYSTEMDINCLUDE)
+  else
+    AC_MSG_WARN([Skipping systemd support])
+  fi
+  LIBS="$_SAVEDLIBS"
+])
+
+
 dnl Check for headers used by check_ide_smart
 case $host in
   *linux*)
diff -wur monitoring-plugins-2.3.3.old/plugins/check_users.c monitoring-plugins-2.3.3/plugins/check_users.c
--- monitoring-plugins-2.3.3.old/plugins/check_users.c	2023-02-01 14:40:55.000000000 +0100
+++ monitoring-plugins-2.3.3/plugins/check_users.c	2023-06-15 16:16:34.879700400 +0200
@@ -48,6 +48,11 @@
 # include "popen.h"
 #endif
 
+#ifdef HAVE_LIBSYSTEMD
+#include <systemd/sd-daemon.h>
+#include <systemd/sd-login.h>
+#endif
+
 #define possibly_set(a,b) ((a) == 0 ? (b) : 0)
 
 int process_arguments (int, char **);
@@ -115,6 +120,11 @@
 
 	WTSFreeMemory(wtsinfo);
 #elif HAVE_UTMPX_H
+#ifdef HAVE_LIBSYSTEMD
+	if (sd_booted () > 0)
+	        users = sd_get_sessions (NULL);
+	else {
+#endif
 	/* get currently logged users from utmpx */
 	setutxent ();
 
@@ -123,6 +133,9 @@
 			users++;
 
 	endutxent ();
+#ifdef HAVE_LIBSYSTEMD
+	}
+#endif
 #else
 	/* run the command */
 	child_process = spopen (WHO_COMMAND);
Nur in monitoring-plugins-2.3.3/plugins: check_users.c~.
diff -wur monitoring-plugins-2.3.3.old/plugins/Makefile.am monitoring-plugins-2.3.3/plugins/Makefile.am
--- monitoring-plugins-2.3.3.old/plugins/Makefile.am	2023-02-01 14:40:55.000000000 +0100
+++ monitoring-plugins-2.3.3/plugins/Makefile.am	2023-06-15 16:23:36.925699810 +0200
@@ -112,7 +112,7 @@
 check_time_LDADD = $(NETLIBS)
 check_ntp_time_LDADD = $(NETLIBS) $(MATHLIBS)
 check_ups_LDADD = $(NETLIBS)
-check_users_LDADD = $(BASEOBJS) $(WTSAPI32LIBS)
+check_users_LDADD = $(BASEOBJS) $(WTSAPI32LIBS) $(SYSTEMDLIBS)
 check_by_ssh_LDADD = $(NETLIBS)
 check_ide_smart_LDADD = $(BASEOBJS)
 negate_LDADD = $(BASEOBJS)