My make of up-to-date LyX-CVS ends with:
In file included from ../../../../boost/boost/regex/config.hpp:54, from cpp_regex_traits.cpp:22: ../../../../boost/boost/cstdint.hpp:121: error: redeclaration of C++ built-in type `long' gmake[4]: *** [cpp_regex_traits.lo] Error 1
This is on FreeBSD (4.10), using Gcc 3.3.4 (20040505).
Rob.