Make sure output buffes are flushed before writing exit code

We have to turn off buffering on bash-level, which can be
conveniently done using the script command.

Author: peterschrammel

regression/test.pl

@@ -26,7 +26,7 @@ ($$$$$)
   my $cmdline = "$cmd $options '$input' >'$output' 2>&1";
 
   print LOG "Running $cmdline\n";
-  system("bash", "-c", "cd '$name' ; $cmdline");
+  system("bash", "-c", "cd '$name' ; script -q /dev/null $cmdline");
   my $exit_value = $? >> 8;
   my $signal_num = $? & 127;
   my $dumped_core = $? & 128;