problem sourcing GDB script in interactive-mode on

When interactive-mode is not auto, GDB always uses that setting to
determine whether to act as if the input stream is a terminal or not.
However, this setting should only be honored if the input stream is
the standard input stream.  Otherwise, we run into trouble while
source-ing a GDB script, as shown below (on x86_64-linux):

        % cat script
        print 1
        print 2
        % gdb  -q
        (gdb) set interactive-mode on
        (gdb) source script
        (gdb) print 3
        $1 = 3

The lack of output and the fact that the "print 3" command returned
a value saved in $1 (as opposed to $3) indicates that the script was
not even evaluated at all.

gdb/ChangeLog:

        * top.c (input_from_terminal_p): Restrict the use of interactive_mode
        to the case where instream is stdin.

gdb/testsuite/ChangeLog:

        * gdb.base/interact.exp: New testcase.

1 files changed, 1 insertions, 1 deletions

diff --git a/gdb/top.c b/gdb/top.c
index d974897ec9..bba1a2ddf5 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1292,7 +1292,7 @@ show_interactive_mode (struct ui_file *file, int from_tty,
 int
 input_from_terminal_p (void)
 {
-  if (interactive_mode != AUTO_BOOLEAN_AUTO)
+  if (interactive_mode != AUTO_BOOLEAN_AUTO && instream == stdin)
     return interactive_mode == AUTO_BOOLEAN_TRUE;
 
   if (batch_flag)