In my earlier mail, I had mysqld segfaulting. On looking further I see
many other programs like nmap, webmin are giving errors. While
rebuilding the system with
emerge -e system
I got an error message from groff complaining of non-working C++
compiler.
Thus, I tried compiling a simple C++ program from a friend, it compiles
fine but I get segfault on it, too, while running.
I am attaching groff error and g++ -v

#groff_error
checking that C++ compiler can compile simple program... yes
checking that C++ static constructors and destructors are called... no
configure: error: a working C++ compiler is required

g++-version
Using built-in specs.
Target: i686-gentoo-freebsd6.2
Configured with: /var/tmp/portage/sys-devel/gcc-4.2.3/work/gcc-4.2.3/configure --prefix=/usr --bindir=/usr/i686-gentoo-freebsd6.2/gcc-bin/4.2.3 --includedir=/usr/lib/gcc/i686-gentoo-freebsd6.2/4.2.3/include --datadir=/usr/share/gcc-data/i686-gentoo-freebsd6.2/4.2.3 --mandir=/usr/share/gcc-data/i686-gentoo-freebsd6.2/4.2.3/man --infodir=/usr/share/gcc-data/i686-gentoo-freebsd6.2/4.2.3/info --with-gxx-include-dir=/usr/lib/gcc/i686-gentoo-freebsd6.2/4.2.3/include/g++-v4 --host=i686-gentoo-freebsd6.2 --build=i686-gentoo-freebsd6.2 --disable-altivec --enable-nls --without-included-gettext --with-system-zlib --disable-checking --disable-werror --enable-secureplt --disable-libunwind-exceptions --disable-libmudflap --disable-libssp --disable-libgcj --with-arch=i686 --enable-languages=c,c++,treelang --enable-shared --enable-threads=posix --enable-__cxa_atexit
Thread model: posix
gcc version 4.2.3 (Gentoo 4.2.3 p1.0)