With SMP activated, no low latency or pre-emptive, and *no* power management, the build fails with an
"undeclared variable" error as follows:
make: Entering directory `/usr/src/linux-2.4.19-gentoo-r4/arch/i386/kernel'
gcc -D__KERNEL__ -I/usr/src/linux-2.4.19-gentoo-r4/include -Wall -Wstrict-prototypes -Wno-trigraphs
-O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -pipe -mpreferred-stack-boundary=2
-march=i686 -nostdinc -I /usr/lib/gcc-lib/i686-pc-linux-gnu/2.95.3/include -DKBUILD_BASENAME=setup
-c -o setup.o setup.c
setup.c: In function `setup_arch':
setup.c:1071: `acpi_mp_config' undeclared (first use in this function)
setup.c:1071: (Each undeclared identifier is reported only once
setup.c:1071: for each function it appears in.)
make: *** [setup.o] Error 1
make: Leaving directory `/usr/src/linux-2.4.19-gentoo-r4/arch/i386/kernel'
make: *** [_dir_arch/i386/kernel] Error 2
*** Bug 2594 has been marked as a duplicate of this bug. ***
*** Bug 2619 has been marked as a duplicate of this bug. ***
this should be fixed in our -r5 kernels which will be hitting rsync soon.