error message when install libxml2

bsazxh

before install libxml2-2.6.31,

./configure

checking build system type... sparc-sun-solaris2.8
checking host system type... sparc-sun-solaris2.8
checking for a BSD-compatible install... ./install-sh -c
checking whether build environment is sane...  configure: error: ls -t appears to fail. Make sure there is not a broken
alias in your environment
configure: error: newly created file is older than distributed files!
Check your system clock

i don't know the reason for the coming error message,.Do you have any idea of it?
Thanks advance

猪知猪之道

Check your system clock