Renamed files from .c to .cc and added new support header files.

Renamed files from .c to .cc and added new support header files.

This patch also includes a mc-boot translated copy of the
module M2Dependent.

gcc/m2/ChangeLog:

	* gm2-libs-ch/UnixArgs.cc: Renamed from gm2-libs-ch/UnixArgs.c.
	* gm2-libs-ch/dtoa.cc: Renamed from gm2-libs-ch/dtoa.c.
	* gm2-libs-ch/ldtoa.cc: Renamed from gm2-libs-ch/ldtoa.c.
	* gm2-libs-ch/m2rts.h: New file.
	* mc-boot-ch/GUnixArgs.cc: New file.
	* mc-boot-ch/m2rts.h: New file.
	* mc-boot/GM2Dependent.c: New file.
	* mc-boot/GM2Dependent.h: New file.

Signed-off-by: Gaius Mulley <gaius.mulley@southwales.ac.uk>