[mutter] mutter: allow building with elogind

[Florian Müllner <fmuellner src gnome org>]

commit 06c357d7819cf2a648e57efe947f5a3cca7d74d2
Author: Rasmus Thomsen <cogitri exherbo org>
Date:   Tue Mar 20 18:23:05 2018 +0100

    mutter: allow building with elogind
    
    This commit allows building mutter with elogind, which is
    systemd-logind extracted into a standalone package. This
    allows using mutter with its native-backend ( and consequently
    wayland ) enabled on distros which use init systems other than
    systemd.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/46

 configure.ac | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 1a625a435..36265b174 100644
--- a/configure.ac
+++ b/configure.ac
@@ -262,7 +262,22 @@ AC_SUBST(XWAYLAND_PATH)
 
 PKG_CHECK_MODULES(MUTTER, $MUTTER_PC_MODULES)
 
-MUTTER_NATIVE_BACKEND_MODULES="libdrm >= 2.4.83 libsystemd libinput >= 1.4 gudev-1.0 gbm >= 17.1"
+PKG_CHECK_MODULES(ELOGIND, [libelogind], [have_elogind=yes], [have_elogind=no])
+
+if test x$have_elogind = xyes; then
+     logind_provider="libelogind"
+fi
+
+PKG_CHECK_MODULES(SYSTEMD, [libsystemd], [have_systemd=yes], [have_systemd=no])
+
+if test x$have_systemd = xyes; then
+     logind_provider="libsystemd"
+fi
+
+AS_IF([test -z "$logind_provider"],
+  AC_MSG_ERROR([Could not find either systemd or elogind as logind provider])])
+
+MUTTER_NATIVE_BACKEND_MODULES="libdrm $logind_provider libinput >= 1.4 gudev-1.0 gbm >= 10.3"
 
 AC_ARG_ENABLE(native-backend,
   AS_HELP_STRING([--disable-native-backend], [disable mutter native (KMS) backend]),,