Export meta_get_replace_current_wm()

This is necessary for gnome-shell to know whether it should try to
replace the org.gnome.Shell DBus name.

Note: We can't just #include <meta/util.h> because it #defines '_'
at least which obviously conflicts with core gettext.  We should
un-export util.h or fix it.

https://bugzilla.gnome.org/show_bug.cgi?id=645590

src/core/screen.c

@@ -28,6 +28,7 @@
 
 #include <config.h>
 #include "screen-private.h"
+#include <meta/main.h>
 #include <meta/util.h>
 #include <meta/errors.h>
 #include "window-private.h"

src/meta/main.h

@@ -29,6 +29,7 @@
 GOptionContext *meta_get_option_context (void);
 void            meta_init               (void);
 int             meta_run                (void);
+gboolean        meta_get_replace_current_wm (void);  /* Actually defined in util.c */
 
 typedef enum
 {

src/meta/util.h

@@ -36,7 +36,6 @@ gboolean meta_is_debugging (void);
 void     meta_set_debugging (gboolean setting);
 gboolean meta_is_syncing (void);
 void     meta_set_syncing (gboolean setting);
-gboolean meta_get_replace_current_wm (void);
 void     meta_set_replace_current_wm (gboolean setting);
 
 void meta_debug_spew_real (const char *format,