AGENT++, SNMP++: requires OPTION_THREADS

After building SNMP++ v3.6.6 with OPTION_THREADS disabled, I encounter build errors of the dependent AGENT++ v4.7.2 build:

include/agent_pp/request.h:904:17: error: use of undeclared identifier 'Synchronized'

include/agent_pp/request.h:904:31: error: no type named 'TryLockResult' in 'Snmp_pp::SnmpSynchronized'

Option a) this is an actual bug.

Option b) AGENT++ is just not supposed to be built without support for threads.
In this case it would be nice to have an #error directive set by AGENT++'s preprocessor with a corresponding error message.

It is option b)of course. I will try to make the error report more clear in the next release.