Format error in m2pp.cc (m2pp_integer_cst) [PR107234]

Use HOST_WIDE_INT_PRINT_UNSIGNED instead of hardcoding a
specific format.

gcc/m2/ChangeLog:

	* m2pp.cc (m2pp_integer_cst): Use
	HOST_WIDE_INT_PRINT_UNSIGNED as the format specifier.

	PR modula2/107234
	    Co-Authored by: Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>