The gentoo guys closed the but with this motivation:
This package has proven to be very unreliable under GCC 3.2, and with
any optimizations in general. As such, it's being moved to an
unsupported status. Issues with the package should be taken to the
developing party www.texmacs.org. The best solution to any problems has
been, in the past, to disable optimizations. If a guaranteed, tried and
tested cross-platform solution to optimization/segfault woes can be
found, we will implement it.
This is crazy; we are not responsible for bugs in the g++ optimizer!
They could just stick to g++ 2.95.3 if g++ 3.2 is bugged.
I'm happy with the static build for now.
In fact, I think that they did not compile g++ 3.2 well;
I managed to build an optimized version of TeXmacs with g++ 3.2
without any problems...