* fhandler.cc (fhandler_base::get_readahead_into_buffer): New function.

* fhandler.h: Declare new function.  Add extra argument to
process_slave_output.
* fhandler_console.cc (fhandler_console::read): Move read ahead code to new
function.
* fhandler_tty.cc (fhandler_pty_master::process_slave_output): Move common code
here.
(fhandler_tty_slave::read): Understand readahead.
(fhandler_pty_master::read): Move code to process_slave_output.
* select.cc (peek_pipe): Avoid performing certain checks when non-read and on
inappropriate fh types.

winsup/cygwin/fhandler.cc

@@ -96,6 +96,24 @@ fhandler_base::eat_readahead (int n)
   return oralen;
 }
 
+int
+fhandler_base::get_readahead_into_buffer (char *buf, size_t buflen)
+{
+  int ch;
+  int copied_chars = 0;
+
+  while (buflen)
+    if ((ch = get_readahead ()) < 0)
+      break;
+    else
+      {
+	buf[copied_chars++] = (unsigned char)(ch & 0xff);
+	buflen--;
+      }
+
+  return copied_chars;
+}
+
 uid_t __stdcall
 get_file_owner (int use_ntsec, const char *filename)
 {