c++: Get rid of convert_like* macros.

c++: Get rid of convert_like* macros.

The convert_like* macros were introduced in

  2000-03-05  Nathan Sidwell  <nathan@codesourcery.com>

        * call.c (convert_like): Macrofy.
        (convert_like_with_context): New macro.

but now we can use overloading so we can do away with the macros.
I've also taken this chance to rename _real to _internal to make it
clear that it should not be called directly.

No functional change intended.

gcc/cp/ChangeLog:

	* call.c (convert_like): Remove macro and introduce a new
	wrapper instead.
	(convert_like_with_context): Likewise.
	(convert_like_real): Rename to convert_like.
	(convert_like_real_1): Rename to convert_like_internal.  Call
	convert_like instead of convert_like_real therein.
	(perform_direct_initialization_if_possible): Call convert_like
	instead of convert_like_real.