* gengtype.c (main): Handle double_int type.
	* tree.h (struct tree_int_cst): Make type of int_cst double_int.
	* double-int.c: New file.
	* double-int.h: New file.
	* system.h: Include doubleint.h.
	* Makefile.in (SYSTEM_H): Include double-int.h.
	(double-int.o): Add.

From-SVN: r111663