Add patches to fix the build with libc++.

Reported by:	theraven@

x11-toolkits/gtkmm20/files/patch-gtk_gtkmm_scale.cc

@@ -0,0 +1,10 @@
+--- gtk/gtkmm/scale.cc.orig	2013-08-31 20:43:53.000000000 +0200
++++ gtk/gtkmm/scale.cc	2013-08-31 20:49:39.000000000 +0200
+@@ -31,6 +31,7 @@
+ #include <gtk/gtkhscale.h>
+ #include <gtk/gtkvscale.h>
+ #include <math.h>
++#include <cstdlib>
+ 
+ namespace Gtk
+ {

x11-toolkits/gtkmm20/files/patch-gtk_gtkmm_treeview.h

@@ -0,0 +1,19 @@
+--- gtk/gtkmm/treeview.h.orig	2013-08-31 15:49:24.000000000 +0200
++++ gtk/gtkmm/treeview.h	2013-08-31 15:59:45.000000000 +0200
+@@ -3,6 +3,7 @@
+ #ifndef _GTKMM_TREEVIEW_H
+ #define _GTKMM_TREEVIEW_H
+ 
++#include <cstdlib>
+ #include <glibmm.h>
+ 
+ /* $Id: treeview.hg,v 1.71 2004/06/03 09:38:35 murrayc Exp $ */
+@@ -1296,7 +1297,7 @@
+     
+     //Convert the text to a number, using the same logic used by GtkCellRendererText when it stores numbers.
+     char* pchEnd = 0;
+-    ColumnType new_value = static_cast<ColumnType>( strtod(new_text.c_str(), &pchEnd) );
++    ColumnType new_value = static_cast<ColumnType>( std::strtod(new_text.c_str(), &pchEnd) );
+ 
+     //Store the user's new text in the model:
+     Gtk::TreeRow row = *iter;