In the file (gentoo-2.4.20-r5 source)/drivers/ide/ide-cd.h in row 440: "__u8 short slot_tablelen;" I don't know why gcc <= 3.2.3 accepts this, but gcc 3.3 and intelC x.x don't. this can be fixed in replacing "__u8 short slot_tablelen;" with "short slot_tablelen;"
this is fixed for gcc3.3 in pfeifer-sources-2.4.20_pre12 which will become gentoo-sources-2.4.20-r6. if you need gcc use this kernel for now.
still happens in 2.4.19-gentoo-r13, -r14, and -r15 No big thing, but this the (AFAIK only) 2.4 gentoo kernel that still contains the cryptoapi patch.
ok now in -r17