[SeaBIOS] git master build failure

[Gerd Hoffmann]

Hi,

$subject says all.

Linking out/rom32seg.o
out/code32seg.o: In function `debug_putc':
/home/kraxel/projects/seabios/src/output.c:42: undefined reference to
`qemu_debug_putc'
/home/kraxel/projects/seabios/src/output.c:45: undefined reference to
`serial_debug_putc'
out/code32seg.o: In function `debug_flush':
/home/kraxel/projects/seabios/src/output.c:52: undefined reference to
`serial_debug_flush'
make: *** [out/rom32seg.o] Error 1

Config attached.  Happens only when configured for coreboot, qemu builds
do just fine.  Can't spot an obvious reason for the build failure
though.

cheers,
  Gerd