The following code is used to test for a trailing [*] in a package
name:

  if (eon-s > 3 && !strncmp(eon-3, "[*]", 3)) {

But if we haven't already found a trailing ']', eon will be NULL.
If the address of s is above 2GB on a 32 bit system, eon-s will
then evaluate to a positive number (assuming 2's complement wraps
round - strictly this is UB), allowing the following strncmp to
access an invalid location.

Fixed by adding an explicit test for NULL before calculating eon-s.

This is used internally to create search queries.
At the same time update synthesis tests to be more representative
by using foo[< 5] syntax which has been what is genereated for
many many years.