make uImage 编译内核时出错

这个问题又折腾了一个下午：

在做RTC驱动时，修改了arch/arm/plat-s3c24xx/common-smdk.c后，编译内核，发现以下错误：

book@www.100ask.org:/work/system/linux-2.6.22.6$ make uImage
  CHK     include/linux/version.h
make[1]: 'include/asm-arm/mach-types.h' is up to date.
  CHK     include/linux/utsrelease.h
  CALL    scripts/checksyscalls.sh
<stdin>:91:1: warning: "__IGNORE_sync_file_range" redefined
In file included from <stdin>:2:
include/asm/unistd.h:444:1: warning: this is the location of the previous definition
<stdin>:1097:2: warning: #warning syscall fadvise64 not implemented
<stdin>:1265:2: warning: #warning syscall migrate_pages not implemented
<stdin>:1321:2: warning: #warning syscall pselect6 not implem