[gtk+] mir: Add C++ guards

[Emmanuele Bassi <ebassi src gnome org>]

commit 90d5c7f9e85cf251db18d889181b0a8878f82309
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Feb 11 11:59:12 2016 +0000

    mir: Add C++ guards
    
    Avoid missing symbols when compiling C++ including the GDK Mir backend
    header.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=761829

 gdk/mir/gdkmir.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gdk/mir/gdkmir.h b/gdk/mir/gdkmir.h
index 22b9173..38cc80c 100644
--- a/gdk/mir/gdkmir.h
+++ b/gdk/mir/gdkmir.h
@@ -21,6 +21,8 @@
 #include <gdk/gdk.h>
 #include <mir_toolkit/mir_client_library.h>
 
+G_BEGIN_DECLS
+
 #define GDK_TYPE_MIR_DISPLAY              (gdk_mir_display_get_type ())
 #define GDK_IS_MIR_DISPLAY(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_MIR_DISPLAY))
 
@@ -45,4 +47,6 @@ MirSurface *gdk_mir_window_get_mir_surface (GdkWindow *window);
 GDK_AVAILABLE_IN_3_16
 GType gdk_mir_gl_context_get_type (void) G_GNUC_CONST;
 
+G_END_DECLS
+
 #endif /* __GDK_MIR_H__ */