Xen devel - Jul 2013 - Compile Problem with Xen 4.3-unstable Changeset 26666

Hi,

I am trying to compile Xen 4.3-unstable changeset 26666 but ran into the 
following problem.

   LINK  i386-dm/qemu-dm
/usr/bin/ld: vl.o: undefined reference to symbol 
''timer_settime@@GLIBC_2.3.3''
/usr/bin/ld: note: ''timer_settime@@GLIBC_2.3.3'' is defined in
DSO
/lib/x86_64-linux-gnu/librt.so.1 so try adding it to the linker command line
/lib/x86_64-linux-gnu/librt.so.1: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status
make[5]: *** [qemu-dm] Error 1
make[5]: Leaving directory 
`/home/teo-en-ming/xen-unstable.hg-cs26666/tools/qemu-xen-traditional-dir-remote/i386-dm''
make[4]: *** [subdir-i386-dm] Error 2
make[4]: Leaving directory 
`/home/teo-en-ming/xen-unstable.hg-cs26666/tools/qemu-xen-traditional-dir-remote''
make[3]: *** [subdir-install-qemu-xen-traditional-dir] Error 2
make[3]: Leaving directory
`/home/teo-en-ming/xen-unstable.hg-cs26666/tools''
make[2]: *** [subdirs-install] Error 2
make[2]: Leaving directory
`/home/teo-en-ming/xen-unstable.hg-cs26666/tools''
make[1]: *** [install-tools] Error 2
make[1]: Leaving directory `/home/teo-en-ming/xen-unstable.hg-cs26666''
make: *** [world] Error 2

Could you help me solve this problem?

Thank you very much.

-- 
Yours sincerely,

Singapore Citizen Mr. Teo En Ming (Zhang Enming)