re PR preprocessor/41943 (include search path composition is bogus)

2010-07-23  Kai Tietz  <kai.tietz@onevision.com>

	PR target/41943
	* Makefile.in (USER_H_INC_NEXT_PRE,
	USER_H_INC_NEXT_POST): New.
	(stmp-int-hdrs): Prefix/postfix headers by include_next.
	* config.gcc (user_headers_inc_next_pre): New.
	(user_headers_inc_next_post): Likewise.
	(*-w64-mingw*): Use for float.h post-fixing, and for
	stddef.h/stdarg.h pre-fixing by include_next.
	* configure.ac (user_headers_inc_next_post): New.
	(user_headers_inc_next_pre): New.
	* configure: Regenerated.

From-SVN: r162479