kernel won't compile (2.6.4)

["r.a." <rabarca@dcc.uchile.cl>]

I've downloaded kernel 2.6.4 from kernel.org and it stops compilation with 
this error:

----------------------------------------------------------------
  CC      drivers/macintosh/macserial.o
drivers/macintosh/macserial.c: In function `rs_tiocmget':
drivers/macintosh/macserial.c:1793: `cmd' undeclared (first use in this 
function)
drivers/macintosh/macserial.c:1793: (Each undeclared identifier is 
reported only once
drivers/macintosh/macserial.c:1793: for each function it appears in.)
drivers/macintosh/macserial.c: In function `rs_tiocmset':
drivers/macintosh/macserial.c:1823: `cmd' undeclared (first use in this 
function)
drivers/macintosh/macserial.c:1813: warning: unused variable `arg'
drivers/macintosh/macserial.c:1813: warning: unused variable `bits'
make[2]: *** [drivers/macintosh/macserial.o] Error 1
make[1]: *** [drivers/macintosh] Error 2
make: *** [drivers] Error 2
----------------------------------------------------------------

If I "fix" it (in a very rudimentary way), it will stop in some other 
file, with another "undeclared identifier" problem.
I'm using gcc 3.2.2 and it's a PowerBook G3 (Lombard 333) with YDL on it.
Do I have to apply some patch to the sources before compiling?
tia!
r.a./