diff --git a/core/Services/Calendar/Store.vala b/core/Services/Calendar/Store.vala
index b67fca072..6ce7f6848 100644
--- a/core/Services/Calendar/Store.vala
+++ b/core/Services/Calendar/Store.vala
@@ -73,7 +73,11 @@ public class Calendar.Store : Object {
     }
 
     private Store () {
+#if HAVE_NL_TIME_FIRST_WEEKDAY
         int week_start = Posix.NLTime.FIRST_WEEKDAY.to_string ().data[0];
+#else
+        int week_start = 1;
+#endif
         if (week_start >= 1 && week_start <= 7) {
             week_starts_on = (GLib.DateWeekday) (week_start - 1);
         }
diff --git a/meson.build b/meson.build
index 98198b324..5d3fab249 100644
--- a/meson.build
+++ b/meson.build
@@ -38,7 +38,17 @@ else
     add_project_arguments('--vapidir', join_paths(meson.current_source_dir(), 'vapi'), language: 'vala')
 endif
 
-m_dep = meson.get_compiler('c').find_library('m', required : false)
+cc = meson.get_compiler('c')
+m_dep = cc.find_library('m', required : false)
+libnotify_dep = dependency('libnotify', required: false)
+
+if libnotify_dep.found()
+    add_project_arguments('--define=HAVE_LIBNOTIFY', language: 'vala')
+endif
+
+if cc.has_header_symbol('langinfo.h', '_NL_TIME_FIRST_WEEKDAY')
+    add_project_arguments('--define=HAVE_NL_TIME_FIRST_WEEKDAY', language: 'vala')
+endif
 
 gresource_calendar = gnome.compile_resources(
     'gresource_calendar',