configure, dist: rework systemd version discovery

With PKG_CHECK_MODULES we select the correct version during cross
compilation.

Signed-off-by: Moritz Buhl <moritz.buhl@infineon.com>

Author: moritzbuhl

configure.ac

@@ -656,11 +656,12 @@ AS_IF([test "x$enable_integration" = "xyes" && test "x$enable_self_generated_cer
 AC_CHECK_PROG(systemd_sysusers, systemd-sysusers, yes)
 AM_CONDITIONAL([SYSD_SYSUSERS], [test "x$systemd_sysusers" = "xyes" && test "x$sysusersdir" != "xno"])
 
-have_systemd_ge_v257=no
+systemd_sysusers_fully_locked=no
 AS_IF([test "x$systemd_sysusers" = "xyes"],
-      [systemd_version=$(systemd-sysusers --version 2>/dev/null | head -1 | cut -d' ' -f2)
-       AS_IF([test -n "$systemd_version" && test "$systemd_version" -ge 257], [have_systemd_ge_v257=yes])])
-AM_CONDITIONAL([SYSD_SYSUSERS_FULLY_LOCKED], [test "x$have_systemd_ge_v257" = "xyes"])
+      [PKG_CHECK_MODULES([LIBSYSTEMD], [libsystemd >= 257],
+                         [systemd_sysusers_fully_locked=yes],
+                         [systemd_sysusers_fully_locked=no])])
+AM_CONDITIONAL([SYSD_SYSUSERS_FULLY_LOCKED], [test "x$systemd_sysusers_fully_locked" = "xyes"])
 
 AC_CHECK_PROG(systemd_tmpfiles, systemd-tmpfiles, yes)
 AM_CONDITIONAL([SYSD_TMPFILES], [test "x$systemd_tmpfiles" = "xyes" && test "x$tmpfilesdir" != "xno"])