[weston] configure.ac: Add support for new versions of systemd

[Javier Jardón]

... that only provide a unique libsystemd.pc file
---
 configure.ac | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index d9d8d8f..561c380 100644
--- a/configure.ac
+++ b/configure.ac
@@ -347,8 +347,12 @@ AS_IF([test "x$have_systemd_login" = "xyes"],
       [AC_DEFINE([HAVE_SYSTEMD_LOGIN], [1], [Have systemd-login])])
 AM_CONDITIONAL(HAVE_SYSTEMD_LOGIN, test "x$have_systemd_login" = "xyes")
 
-PKG_CHECK_MODULES(SYSTEMD_LOGIN_209, [libsystemd-login >= 209],
-                  [have_systemd_login_209=yes], [have_systemd_login_209=no])
+PKG_CHECK_MODULES([SYSTEMD_LOGIN_209],
+                  [libsystemd >= 209],
+                  [have_systemd_login_209=yes],
+                  [PKG_CHECK_MODULES([SYSTEMD_LOGIN_209],
+                                     [libsystemd-login >= 209],
+                                     [have_systemd_login_209=yes], [have_systemd_login_209=no])])
 AS_IF([test "x$have_systemd_login_209" = "xyes"],
       [AC_DEFINE([HAVE_SYSTEMD_LOGIN_209], [1], [Have systemd-login >= 209])])
 
-- 
2.3.2