configure.in: Add AC_CHECK_TYPE(ssize_t).

configure.in: Add AC_CHECK_TYPE(ssize_t).

	* configure.in: Add AC_CHECK_TYPE(ssize_t).  Remove commented
	out check for wchar_t.
	* acconfig.h: Add template for ssize_t.  Remove @TOP@.
	* system.h: Add infrastructure for defining missing
	TYPE_MAX/TYPE_MIN macros.  Use it to provide fallback
	definitions of UCHAR_MAX and SSIZE_MAX.
	* configure: Regenerate.
	* config.in: Regenerate.

From-SVN: r34212