make  check-am
make[2]: Entering directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
  CC       libxfce4ui_2_la-libxfce4ui-aliasdef.lo
  CC       libxfce4ui_2_la-libxfce4ui-enum-types.lo
  CC       libxfce4ui_2_la-libxfce4ui-marshal.lo
  CC       libxfce4ui_2_la-libxfce4ui-resources.lo
  CC       libxfce4ui_2_la-libxfce4ui-config.lo
  CC       libxfce4ui_2_la-xfce-dialogs.lo
  CC       libxfce4ui_2_la-xfce-gdk-extensions.lo
xfce-gdk-extensions.c: In function ‘IA__xfce_gdk_screen_get_geometry’:
xfce-gdk-extensions.c:127:3: warning: ‘gdk_display_get_n_monitors’ is deprecated: Not available before 3.22 [-Wdeprecated-declarations]
   num_monitors = gdk_display_get_n_monitors (display);
   ^~~~~~~~~~~~
In file included from /usr/include/gtk-3.0/gdk/gdkscreen.h:32:0,
                 from /usr/include/gtk-3.0/gdk/gdkapplaunchcontext.h:31,
                 from /usr/include/gtk-3.0/gdk/gdk.h:32,
                 from ../libxfce4ui/xfce-gdk-extensions.h:28,
                 from xfce-gdk-extensions.c:39:
/usr/include/gtk-3.0/gdk/gdkdisplay.h:183:14: note: declared here
 int          gdk_display_get_n_monitors        (GdkDisplay *display);
              ^~~~~~~~~~~~~~~~~~~~~~~~~~
xfce-gdk-extensions.c:134:7: warning: ‘gdk_display_get_monitor’ is deprecated: Not available before 3.22 [-Wdeprecated-declarations]
       monitor = gdk_display_get_monitor (display, i);
       ^~~~~~~
In file included from /usr/include/gtk-3.0/gdk/gdkscreen.h:32:0,
                 from /usr/include/gtk-3.0/gdk/gdkapplaunchcontext.h:31,
                 from /usr/include/gtk-3.0/gdk/gdk.h:32,
                 from ../libxfce4ui/xfce-gdk-extensions.h:28,
                 from xfce-gdk-extensions.c:39:
/usr/include/gtk-3.0/gdk/gdkdisplay.h:185:14: note: declared here
 GdkMonitor * gdk_display_get_monitor           (GdkDisplay *display,
              ^~~~~~~~~~~~~~~~~~~~~~~
xfce-gdk-extensions.c:135:7: warning: ‘gdk_monitor_get_geometry’ is deprecated: Not available before 3.22 [-Wdeprecated-declarations]
       gdk_monitor_get_geometry (monitor, &rect);
       ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/gtk-3.0/gdk/gdkdisplay.h:34:0,
                 from /usr/include/gtk-3.0/gdk/gdkscreen.h:32,
                 from /usr/include/gtk-3.0/gdk/gdkapplaunchcontext.h:31,
                 from /usr/include/gtk-3.0/gdk/gdk.h:32,
                 from ../libxfce4ui/xfce-gdk-extensions.h:28,
                 from xfce-gdk-extensions.c:39:
/usr/include/gtk-3.0/gdk/gdkmonitor.h:71:19: note: declared here
 void              gdk_monitor_get_geometry        (GdkMonitor   *monitor,
                   ^~~~~~~~~~~~~~~~~~~~~~~~
  CC       libxfce4ui_2_la-xfce-gtk-extensions.lo
  CC       libxfce4ui_2_la-xfce-heading.lo
  CC       libxfce4ui_2_la-xfce-sm-client.lo
  CC       libxfce4ui_2_la-xfce-spawn.lo
  CC       libxfce4ui_2_la-xfce-titled-dialog.lo
  CCLD     libxfce4ui-2.la
make  check-TESTS
make[3]: Entering directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
make[4]: Entering directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
FAIL: abicheck.sh
============================================================================
Testsuite summary for libxfce4ui 4.14.1
============================================================================
# TOTAL: 1
# PASS:  0
# SKIP:  0
# XFAIL: 0
# FAIL:  1
# XPASS: 0
# ERROR: 0
============================================================================
See libxfce4ui/test-suite.log
Please report to https://bugzilla.xfce.org/
============================================================================
Makefile:1388: recipe for target 'test-suite.log' failed
make[4]: *** [test-suite.log] Error 1
make[4]: Leaving directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
Makefile:1494: recipe for target 'check-TESTS' failed
make[3]: *** [check-TESTS] Error 2
make[3]: Leaving directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
Makefile:1573: recipe for target 'check-am' failed
make[2]: *** [check-am] Error 2
make[2]: Leaving directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
Makefile:1575: recipe for target 'check' failed
make[1]: *** [check] Error 2
make[1]: Leaving directory '/home/jc/Downloads/src/libxfce4ui-4.14.1/libxfce4ui'
Makefile:542: recipe for target 'check-recursive' failed
make: *** [check-recursive] Error 1


Problem occurs under ubuntu:
uname -a
Linux jc-VirtualBox 4.15.0-51-generic #55-Ubuntu SMP Wed May 15 14:27:21 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
running under virtual box 6.0.14 r133895 (Qt5.6.3)