systems. Since process identifiers are always integers, killing a non-numeric
process is now fatal.
+=item C<-C> on the shebang line is once more permitted
+
+if it is also specified on the command line. C<-C> on the shebang line used
+to be a silent no-op I<if> it was not also on the command line, so perl
+5.10.0 disallowed it, which broke some scripts. Now perl checks whether it
+is also on the command line and only dies if it is not.
+
=back
=head1 New or Changed Diagnostics