/devel/root on FreeBSD 7.0

And what should I do to install it on my FreeBSD 7.0? (while I still don`t belive that it is really impossible)
Let's say you have gcc34 installed on your system

1) cd /usr/ports/devel/root
2) vim Makefile

add "USE_GCC=3.4"

3) make install clean

Doesn't that work?
cint/src/gcc3strm.cxx:168: error: 'class std::fpos<__mbstate_t>' has no member named 'operator=='
cint/src/gcc3strm.cxx: In function 'int G__G__stream_5_8_0(G__value*, const char*, G__param*, int)':
cint/src/gcc3strm.cxx:173: error: 'class std::fpos<__mbstate_t>' has no member named 'operator!='
gmake: *** [cint/src/gcc3strm.o] Error 1
*** Error code 2

But it was better, than with gcc3.3...

I have no idea, why it is so. Maybe, I should deinstall gcc4.2 manually and install gcc3.4? (because, as I see, it is installed as dependency during root compilation, and I think, it is used for compilation... or have I been mistaken?)