A g++-compatible demangler named c++filt can be found in the
`binutils' distribution. This distribution (which also contains
the GNU linker) can be found at any GNU archive site.
As of version 2.7.0, c++filt is included with gcc and is
installed automatically. Even better, it is used by the collect
linker, so you don't see mangled symbols anymore (except on platforms
that use neither collect nor the GNU linker, like Solaris).