Make-lang.in (convert.o): Depend on convert.h.

Make-lang.in (convert.o): Depend on convert.h.

	* Make-lang.in (convert.o): Depend on convert.h.
	* convert.c: Header and comment cleanups.
	(gfc_thruthvalue_conversion): Rename static function
	to truthvalue_conversion.  Do not use 'internal_error' from here,
	use 'gcc_unreachable' instead.
	(convert): Do not use 'error' for conversions to void, use
	'gcc_unreachable' instead.  Likewise for conversions to non-scalar
	types.  Do not hanlde ENUMERAL_TYPE, the front end never creates them.
	Clean up #if 0 code.

From-SVN: r185160