unbound-1.4.17 fails to compile with threads support

[Phil Stone]

It seems that port dns/unbound compiles without threads support
regadless of port options.

In dns/unbound/Makefile:91

.if empty(${PORT_OPTIONS:MTHREADS})
CONFIGURE_ARGS+=--without-pthreads
.endif

sets --without-pthreads regadless of THREADS option.

Changing to:

.if !${PORT_OPTIONS:MTHREADS}
CONFIGURE_ARGS+=--without-pthreads
.endif

provides the correct behavior.

Best Regards,
Phil