GCC doesn't want to compile

[dante%mbox.vol.it@localhost (Dante Profeta)]

I downloaded gcc (27 april updated), but it doesn't want to compile:

-------------------------
In file included from
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/new.h:6, from
AllocRing.cc:24:
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:25:
declaration of `__nw' as array of functions
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:25: `__nw'
redeclared as different kind of symbol
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:24:
previous declaration of `void * operator new (unsigned int)'
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:27:
declaration of `__dl' as array of functions
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:27: `__dl'
redeclared as different kind of symbol
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:26:
previous declaration of `void  operator delete (void *)'
/usr/local/src/gnu/lib/libg++/libg++/src/../../libstdc++/std/new.h:31: syntax
error before `{'
*** Error code 1

Stop.
*** Error code 1

Stop.
*** Error code 1

Stop.
*** Error code 1

Stop.
*** Error code 1

Stop.
-------------------------

That's all.
What have I do?

Thanks in advance.