...
  CC      mm/util.o
  CC      kernel/timer.o
  CC      arch/i386/kernel/cpu/nexgen.o
  CC      arch/i386/kernel/cpu/umc.o
kernel/timer.c: In function ‘sys_getpid’:
kernel/timer.c:1249: warning: implicit declaration of function ‘vx_map_tgid’
kernel/timer.c: In function ‘sys_getppid’:
kernel/timer.c:1265: warning: implicit declaration of function ‘vx_map_pid’
kernel/timer.c: In function ‘sys_sysinfo’:
kernel/timer.c:1442: warning: implicit declaration of function ‘vx_flags’
kernel/timer.c:1442: error: ‘VXF_VIRT_UPTIME’ undeclared (first use in this function)
kernel/timer.c:1442: error: (Each undeclared identifier is reported only once
kernel/timer.c:1442: error: for each function it appears in.)
kernel/timer.c:1443: warning: implicit declaration of function ‘vx_vsi_uptime’
make[2]: *** [kernel/timer.o] Error 1
make[1]: *** [kernel] Error 2
make[1]: *** Waiting for unfinished jobs....