CONFIG_PCI=n, CONFIG_HT_IRQ=y results in the following compile error:

...
  LD      vmlinux
arch/i386/mach-generic/built-in.o: In function `apicid_to_node':
summit.c:(.text+0x53): undefined reference to `apicid_2_node'
arch/i386/kernel/built-in.o: In function `arch_setup_ht_irq':
(.text+0xcf79): undefined reference to `write_ht_irq_low'
arch/i386/kernel/built-in.o: In function `arch_setup_ht_irq':
(.text+0xcf85): undefined reference to `write_ht_irq_high'
arch/i386/kernel/built-in.o: In function `k7nops':
alternative.c:(.data+0x1358): undefined reference to `mask_ht_irq'
alternative.c:(.data+0x1360): undefined reference to `unmask_ht_irq'
make[1]: *** [vmlinux] Error 1

Bug report by Jesper Juhl.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>