patch attached, I've no idea what I've done really, but it builds ok now.

This time on an x86 box:

wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/linux-2.6.14.tar.bz2
wget ftp://ftp.kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.15-rc1.bz2
wget http://user-mode-linux.sourceforge.net/work/current/2.6/2.6.15-rc1/patches.tar
tar -xf patches.tar
tar -jxf linux-2.6.14.tar.bz2
mv linux-2.6.14 linux-2.6.15-rc1-uml
cd linux-2.6.15-rc1-uml
bzcat ../patch-2.6.15-rc1.bz2 | patch -p1
for patch in `cat ../patches/series`; do echo $patch; patch -p1 < ../patches/$patch;  done
find . -type f -size 0 -exec rm {} \;
make ARCH=um defconfig
make ARCH=um vmlinux
  LD      arch/um/drivers/net.o
  LD      arch/um/drivers/mconsole.o
  LD      arch/um/drivers/ubd.o
  CC      arch/um/drivers/null.o
  LD      arch/um/drivers/port.o
  CC      arch/um/drivers/pty.o
  CC      arch/um/drivers/tty.o
  CC      arch/um/drivers/cow_user.o
  CC      arch/um/drivers/random.o
  LD      arch/um/drivers/built-in.o
  CC      arch/um/os-Linux/aio.o
arch/um/os-Linux/aio.c: In function ‘init_aio_26’:
arch/um/os-Linux/aio.c:402: error: ‘finish_aio_26’ undeclared (first use in this function)
arch/um/os-Linux/aio.c:402: error: (Each undeclared identifier is reported only once
arch/um/os-Linux/aio.c:402: error: for each function it appears in.)
make[1]: *** [arch/um/os-Linux/aio.o] Error 1
make: *** [arch/um/os-Linux] Error 2

Antoine