(main): Don't die when dev/ino of input and output are

the same and the file descriptors correspond to stdin and stdout.
This is necessary on at least Digital UNIX (aka OSF1) 3.2C.
Otherwise, running `cat << X > $$' would fail with `cat: -: input
file is output file'.  From Jarkko Hietaniemi <jhi@epsilon.hut.fi>.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/cat.c b/src/cat.c
index 77dec0e2e..0038c1921 100644
--- a/src/cat.c
+++ b/src/cat.c
@@ -654,7 +654,8 @@ main (int argc, char **argv)
 	 files cannot be redirected to themselves.  */
 
       if (check_redirection
-	  && stat_buf.st_dev == out_dev && stat_buf.st_ino == out_ino)
+	  && stat_buf.st_dev == out_dev && stat_buf.st_ino == out_ino
+	  && (input_desc != fileno (stdin) || output_desc != fileno (stdout)))
 	{
 	  error (0, 0, _("%s: input file is output file"), infile);
 	  exit_stat = 1;