[gnome-desktop] Revert "Revert "Use xlocale.h - fixes build on MacOS (possibly also FreeBSD)""

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 7fe06d61c83ac8a3870d822e797975b91b4a056c
Author: Dan Cîrnaț <cirnatdan NetBSD org>
Date:   Thu Apr 15 16:10:25 2021 +0200

    Revert "Revert "Use xlocale.h - fixes build on MacOS (possibly also FreeBSD)""
    
    This reverts commit df40d5d46e210c242820adf604293a7bb07dea4f.

 libgnome-desktop/gnome-gettext-portable.c | 3 +++
 libgnome-desktop/gnome-gettext-portable.h | 4 ++++
 meson.build                               | 1 +
 tests/wall-clock.c                        | 2 ++
 4 files changed, 10 insertions(+)
---
diff --git a/libgnome-desktop/gnome-gettext-portable.c b/libgnome-desktop/gnome-gettext-portable.c
index aaba4d08..75083eb2 100644
--- a/libgnome-desktop/gnome-gettext-portable.c
+++ b/libgnome-desktop/gnome-gettext-portable.c
@@ -20,6 +20,9 @@
 #include "config.h"
 
 #include <locale.h>
+#ifdef HAVE_XLOCALE
+#include <xlocale.h>
+#endif
 
 #include <glib.h>
 #include <glib/gi18n-lib.h>
diff --git a/libgnome-desktop/gnome-gettext-portable.h b/libgnome-desktop/gnome-gettext-portable.h
index c8af3691..9dd65712 100644
--- a/libgnome-desktop/gnome-gettext-portable.h
+++ b/libgnome-desktop/gnome-gettext-portable.h
@@ -23,6 +23,10 @@
 #include <locale.h>
 #include <string.h>
 
+#ifdef HAVE_XLOCALE
+#include <xlocale.h>
+#endif
+
 const char * 
 dgettext_l (locale_t    locale,
             const char *domain,
diff --git a/meson.build b/meson.build
index 490d43e6..00cf25fb 100644
--- a/meson.build
+++ b/meson.build
@@ -95,6 +95,7 @@ conf.set('HAVE_XKBREGISTRY', xkbregistry_dep.found())
 conf.set('HAVE_TIMERFD', cc.has_function('timerfd_create'))
 conf.set('HAVE_OPENAT', cc.has_function('openat'))
 conf.set('HAVE_USELOCALE', cc.has_function('uselocale'))
+conf.set('HAVE_XLOCALE', cc.has_header('xlocale.h'))
 
 config_h = declare_dependency(
   sources: configure_file(
diff --git a/tests/wall-clock.c b/tests/wall-clock.c
index a980c951..44bc93bb 100644
--- a/tests/wall-clock.c
+++ b/tests/wall-clock.c
@@ -17,6 +17,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
+#include "config.h"
+
 #include <gdesktop-enums.h>
 #include <glib.h>
 #define GNOME_DESKTOP_USE_UNSTABLE_API