re PR libstdc++/7744 (streambuf::in_avail() always returns 0 (zero) for cin input...

re PR libstdc++/7744 (streambuf::in_avail() always returns 0 (zero) for cin input stream)

2003-03-09  Paolo Carlini  <pcarlini@unitus.it>
	    Nathan Myers  <ncm@cantrip.org>

	PR libstdc++/7744
	* config/io/basic_file_stdio.h (__basic_file<>::xsgetn, xsputn,
	seekoff, seekpos): Add a boolean parameter __stdio.
	* config/io/basic_file_stdio.cc (__basic_file<>::xsgetn, xsputn,
	seekoff, seekpos): If __stdio == true, use fread (fwrite, fseek/ftell,
	fseek/ftell, respectively), otherwise read (write, lseek, lseek,
	respectively).
	* include/bits/fstream.tcc (basic_filebuf<>::_M_convert_to_external,
	_M_really_overflow, seekoff): Use the boolean parameter in the calls.
	* include/std/std_fstream.h (sync): Likewise.
	* src/fstream.cc (basic_filebuf<>::_M_underflow_common): Likewise.
	* src/ios.cc (ios_base::Init::_S_ios_create(bool)): Revert libstdc++/8399
	commit involving isatty(0).
	* acinclude.m4 (GLIBCPP_CHECK_UNISTD_DECL_AND_LINKAGE_1): Remove.
        (GLIBCPP_CHECK_UNISTD_SUPPORT): Remove
  	* configure.in: Remove call.
	* aclocal.m4: Regenerate.
       	* config.h.in: Regenerate.
        * configure: Regenerate.
	* testsuite/27_io/narrow_stream_objects.cc (test11): Add.

Co-Authored-By: Nathan Myers <ncm@cantrip.org>
From-SVN: r64051