x86_64 fails to build

 |  ==> Starting build()...
 |  Building local GSettings schema...
 |  make  all-recursive
 |  make[1]: Entering directory '/build/california/src/california-0.4.0'
 |  Making all in src
 |  make[2]: Entering directory '/build/california/src/california-0.4.0/src'
 |  rm -f california_vala.stamp && echo stamp > california_vala.stamp-t
 |  CDPATH="${ZSH_VERSION+.}:" && cd . && /usr/bin/valac --debug --enable-checking --vapidir ../vapi --target-glib=2.38 --enable-deprecated --gresources=california-resources.xml  --define HAVE__NL_TIME_FIRST_WEEKDAY --fatal-warnings --pkg gtk+-3.0 --pkg gio-2.0 --pkg posix --pkg gee-0.8 --pkg libedataserver-1.2 --pkg libecal-1.2 --pkg libical --pkg libsoup-2.4 --pkg libgdata --pkg Goa-1.0 --pkg langinfo   -C activator/activator.vala activator/activator-instance.vala activator/activator-instance-list.vala activator/caldav/caldav-activator-instance.vala activator/caldav/caldav-subscribe.vala activator/generic/generic-subscribe.vala activator/google/google-activator-instance.vala activator/google/google-authenticating-pane.vala activator/google/google-calendar-list-pane.vala activator/google/google-login-pane.vala activator/webcal/webcal-activator-instance.vala activator/webcal/webcal-subscribe.vala application/california-application.vala application/california-commandline.vala application/california-resource.vala application/california-settings.vala application/main.vala backing/backing.vala backing/backing-caldav-subscribable.vala backing/backing-calendar-source.vala backing/backing-calendar-source-subscription.vala backing/backing-calendar-subscription-manager.vala backing/backing-error.vala backing/backing-manager.vala backing/backing-source.vala backing/backing-store.vala backing/backing-webcal-subscribable.vala backing/eds/backing-eds-calendar-source.vala backing/eds/backing-eds-calendar-source-subscription.vala backing/eds/backing-eds-store.vala base/base-object.vala base/base-unit.vala calendar/calendar.vala calendar/calendar-date-span.vala calendar/calendar-day-of-month.vala calendar/calendar-day-of-week.vala calendar/calendar-date.vala calendar/calendar-date-ordering.vala calendar/calendar-dbus.vala calendar/calendar-duration.vala calendar/calendar-error.vala calendar/calendar-exact-time.vala calendar/calendar-exact-time-span.vala calendar/calendar-first-of-week.vala calendar/calendar-month.vala calendar/calendar-month-of-year.vala calendar/calendar-month-span.vala calendar/calendar-olson-zone.vala calendar/calendar-span.vala calendar/calendar-system.vala calendar/calendar-timezone.vala calendar/calendar-unit.vala calendar/calendar-unit-span.vala calendar/calendar-wall-time.vala calendar/calendar-week.vala calendar/calendar-week-span.vala calendar/calendar-year.vala calendar/calendar-year-span.vala collection/collection.vala collection/collection-iterable.vala collection/collection-lookahead-stack.vala collection/collection-simple-iterator.vala collection/collection-simple-iterable.vala component/component.vala component/component-date-time.vala component/component-details-parser.vala component/component-error.vala component/component-event.vala component/component-icalendar.vala component/component-instance.vala component/component-person.vala component/component-recurrence-rule.vala component/component-uid.vala component/component-vtype.vala event-editor/event-editor.vala event-editor/event-editor-attendees-card.vala event-editor/event-editor-date-time-card.vala event-editor/event-editor-date-time-widget.vala event-editor/event-editor-deck.vala event-editor/event-editor-main-card.vala event-editor/event-editor-recurring-card.vala host/host.vala host/host-calendar-list-item.vala host/host-import-calendar.vala host/host-main-window.vala host/host-main-window-title.vala host/host-quick-create-event.vala host/host-show-event.vala manager/manager.vala manager/manager-calendar-list.vala manager/manager-calendar-list-item.vala manager/manager-remove-calendar.vala manager/manager-window.vala tests/tests.vala tests/tests-calendar-date.vala tests/tests-calendar-exact-time.vala tests/tests-calendar-exact-time-span.vala tests/tests-calendar-month-of-year.vala tests/tests-calendar-month-span.vala tests/tests-calendar-wall-time.vala tests/tests-iterable.vala tests/tests-quick-add.vala tests/tests-quick-add-recurring.vala tests/tests-string.vala toolkit/toolkit.vala toolkit/toolkit-button-connector.vala toolkit/toolkit-button-event.vala toolkit/toolkit-calendar-popup.vala toolkit/toolkit-card.vala toolkit/toolkit-combo-box-text-model.vala toolkit/toolkit-deck.vala toolkit/toolkit-deck-popover.vala toolkit/toolkit-deck-window.vala toolkit/toolkit-editable-label.vala toolkit/toolkit-entry-clear-text-connector.vala toolkit/toolkit-entry-filter-connector.vala toolkit/toolkit-event-connector.vala toolkit/toolkit-listbox-model.vala toolkit/toolkit-motion-connector.vala toolkit/toolkit-motion-event.vala toolkit/toolkit-mutable-widget.vala toolkit/toolkit-popup.vala toolkit/toolkit-region-manager.vala toolkit/toolkit-rotating-button-box.vala toolkit/toolkit-stack-model.vala util/util.vala util/util-email.vala util/util-gfx.vala util/util-markup.vala util/util-memory.vala util/util-numeric.vala util/util-scheduled.vala util/util-string.vala util/util-uri.vala unit-test/unit-test-harness.vala view/view.vala view/view-chronology-motion.vala view/view-container.vala view/view-controllable.vala view/view-palette.vala view/agenda/agenda.vala view/agenda/agenda-controller.vala view/agenda/agenda-date-row.vala view/agenda/agenda-event-row.vala view/agenda/agenda-load-more-row.vala view/common/common.vala view/common/common-events-cell.vala view/common/common-instance-container.vala view/month/month.vala view/month/month-cell.vala view/month/month-controller.vala view/month/month-grid.vala view/week/week.vala view/week/week-all-day-cell.vala view/week/week-controller.vala view/week/week-day-pane.vala view/week/week-grid.vala view/week/week-hour-runner.vala view/week/week-pane.vala
 |  calendar/calendar-dbus.vala:32.5-32.33: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void set_time(int64 usec_etc, bool relative, bool user_interaction) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:33.5-33.37: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void set_timezone(string timezone, bool user_interaction) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:34.5-34.38: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void set_local_rtc(bool local_rtc, bool fix_system, bool user_interaction)
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:36.5-36.32: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void set_ntp(bool use_ntp, bool user_interaction) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:52.5-52.31: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract Variant get(string interf, string property) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:53.5-53.32: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void get_all(string interf, HashTable<string, Variant> properties) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 |  calendar/calendar-dbus.vala:54.5-54.28: warning: DBus methods are recommended to throw at least `GLib.Error' or `GLib.DBusError, GLib.IOError'
 |      public abstract void set(string interf, string property, Variant value) throws IOError;
 |      ^^^^^^^^^^^^^^^^^^^^^^^^
 |  component/component-date-time.vala:38.5-38.27: warning: California.Component.DateTime.is_floating hides inherited property `GLib.Object.is_floating'. Use the `new' keyword if hiding was intentional
 |      public bool is_floating { get { return zone == null && !is_date; } }
 |      ^^^^^^^^^^^^^^^^^^^^^^^
 |  Compilation failed: 0 error(s), 8 warning(s)
 |  make[2]: *** [Makefile:4649: california_vala.stamp] Error 1
 |  make[2]: Leaving directory '/build/california/src/california-0.4.0/src'
 |  make[1]: *** [Makefile:561: all-recursive] Error 1
 |  make[1]: Leaving directory '/build/california/src/california-0.4.0'
 |  make: *** [Makefile:414: all] Error 2
 |  ==> ERROR: A failure occurred in build().
 |      Aborting...
==> Copying log and package files out of the chroot...