PANICTRACE option parsing

PANICTRACE option parsing

Fix the situation where disabling PANICTRACE, which happened implicitly
when BETA  got disabled, caused SYSCF option processing to complain and
quit if the 'sysconf' file contained any PANICTRACE settings.

Now accept all the PANICTRACE options (assuming SYSCF is defined) even
if PANICTRACE is not defined.  Their values are recorded in the 'sysopt'
struct, but only validated when the appropriate macros (PANICTRACE,
PANICTRACE_LIB) are defined.