fix warning about overflow if matiec is running on 64-bit platform,
but the generated C code will cross-compiled for 32-bit platform

For example:
./build/config.c:29:39: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
unsigned long greatest_tick_count__ = 18446744073709551611UL; /*tick*/
^
compilation terminated due to -Wfatal-errors.
cc1: all warnings being treated as errors

matiec (2009.0-%DATEVERSION%) unstable; urgency=low

  * Initial release (Closes: #nnnn)  <nnnn is the bug number of your ITP>

 -- edouard <edouard.tisserant@gmail.com>  Wed, 21 Nov 2007 17:01:50 +0100