patch: explicit eof check

When patching a file that has already been patched, the line loop contains a nested "readline" which needs to terminate the loop if EOF is detected. I put this in a new commit so the last commit was more obvious that it was only restoring old code.

Author: mknos

bin/patch

@@ -867,6 +867,10 @@ sub index {
             my $fail;
             for (1..$#$match) {
                 my $line = <$in>;
+                unless (defined $line) {
+                    $fail++;
+                    last;
+                }
                 $line =~ s/\s+/ /g if $self->{'ignore-whitespace'};
                 $line eq $match->[$_] or $fail++, last;
             }