When preprocessing a source, it is now possible to use comparaison of
symbols with integers, using operators =, <, <=, > or >=, as in:

#if symbol = 3

#if symbol <= 20

Tested on x86_64-pc-linux-gnu, committed on trunk

2013-10-14  Vincent Celier  <celier@adacore.com>

	* prep.adb (Expression): Accept terms of the form 'symbol <relop>
	integer", where relop is =, <, <=, > or >=.
	(Parse_Def_File): Accept literal integer values.
	* gcc-interface/Make-lang.in: Add s-valint.o, s-valuns.o and
	s-valuti.o to the compiler object files.