fstream.tcc (overflow): According to 27.5.2.4.5, overflow() returns not_eof(eof()).

2003-06-10  Paolo Carlini  <pcarlini@unitus.it>

	* include/bits/fstream.tcc (overflow): According to
	27.5.2.4.5, overflow() returns not_eof(eof()).
	* testsuite/27_io/basic_filebuf/overflow/char/2.cc: New.
	* testsuite/27_io/basic_filebuf/overflow/char/2-unbuf.cc: Ditto.

2003-06-10  Paolo Carlini  <pcarlini@unitus.it>

	* include/bits/fstream.tcc (_M_underflow): Check overflow return
	value; tweak slightly.

From-SVN: r67726