ecore_drm: Setup correct linker flags for usage with systemd-login

After the introduction of the non-systemd launcher the linking with systemd
enabled failed for me.

lib/ecore_drm/.libs/libecore_drm.so: undefined reference to `sd_pid_get_session'

Better we make sure that we actually setup the linker flags for the systemd use
case as well.

src/Makefile_Ecore_Drm.am

@@ -34,6 +34,9 @@ lib_ecore_drm_libecore_drm_la_CPPFLAGS = \
   -DMODULE_ARCH=\"$(MODULE_ARCH)\"
 
 lib_ecore_drm_libecore_drm_la_LIBADD = @ECORE_DRM_LIBS@
+if HAVE_SYSTEMD_LOGIN
+lib_ecore_drm_libecore_drm_la_LIBADD += @SYSTEMD_LOGIN_LIBS@
+endif
 lib_ecore_drm_libecore_drm_la_DEPENDENCIES = @ECORE_DRM_INTERNAL_LIBS@
 lib_ecore_drm_libecore_drm_la_LDFLAGS = @EFL_LTLIBRARY_FLAGS@