[boost] [config] fix for BCB and BOOST_NO_MEMBER_TEMPLATE_FRIENDS

I believe config macro BOOST_NO_MEMBER_TEMPLATE_FRIENDS should be defined for BCB 6. Currently it is defined only for BCB 5.5.1 and less but with BCB 6: - compiling test file boost_no_mem_templ_frnds.cxx fails, - the problem shows in Serialization library too. So I recommend to change borland.hpp to define this macro for BCB 6 (and likely for Kylix which is simply BCB6 ported to Linux). BCB6 patch 4 == 0x564 Kylix = 0x570 /Pavel