re GNATS libgcj/15 (_REENTRANT should be defined more consistently)

re GNATS libgcj/15 (_REENTRANT should be defined more consistently)

	Fix for PR libgcj/15:
	* java/util/natGregorianCalendar.cc (_REENTRANT,
	_POSIX_PTHREAD_SEMANTICS): Don't define.
	* java/net/natInetAddress.cc (_REENTRANT): Don't define.
	* java/lang/natSystem.cc (_REENTRANT, _POSIX_PTHREAD_SEMANTICS):
	Don't define.
	* java/io/natFile.cc (_REENTRANT, _POSIX_PTHREAD_SEMANTICS): Don't
	define.
	* configure: Rebuilt.
	* configure.in: If using POSIX threads, define _REENTRANT if
	needed.  Define _POSIX_PTHREAD_SEMANTICS.  Don't define
	GETHOSTBYNAME_R_NEEDS_REENTRANT.

From-SVN: r33318