[gtkmm] RadioItem: Make a constructor explicit.

[Murray Cumming <murrayc src gnome org>]

commit 67fe03b0d8789a6b89ac772d1d6cb8f59beb8a7c
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Dec 12 10:17:26 2016 +0100

    RadioItem: Make a constructor explicit.
    
    Noticed by cppcheck.

 gtk/src/radiomenuitem.hg |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/src/radiomenuitem.hg b/gtk/src/radiomenuitem.hg
index bcda32c..e935a52 100644
--- a/gtk/src/radiomenuitem.hg
+++ b/gtk/src/radiomenuitem.hg
@@ -45,7 +45,7 @@ public:
    */
   explicit RadioMenuItem(const Glib::ustring& label, bool mnemonic = false);
 
-  RadioMenuItem(Group& groupx);
+  explicit RadioMenuItem(Group& groupx);
   _IGNORE(gtk_radio_menu_item_new)
   RadioMenuItem(Group& groupx, const Glib::ustring& label, bool mnemonic = false);
   _IGNORE(gtk_radio_menu_item_new_with_label, gtk_radio_menu_item_new_with_mnemonic)