graphics/blender: prepare for upcoming Boost 1.81

graphics/blender/files/patch-intern_locale_boost__locale__wrapper.cpp

+https://bugs.gentoo.org/887059
+
+Adding include as suggested by the compiler:
+
+"intern/locale/boost_locale_wrapper.cpp:12:1: note: ‘std::cout’ is defined 
+in header ‘<iostream>’; did you forget to ‘#include <iostream>’?"
+
+--- intern/locale/boost_locale_wrapper.cpp
++++ intern/locale/boost_locale_wrapper.cpp
+@@ -9,6 +9,7 @@
+ #include <stdio.h>
+ 
+ #include "boost_locale_wrapper.h"
++#include <iostream>
+ 
+ static std::string messages_path;
+ static std::string default_domain;