Mk/bsd.port.mk PORTS_FEATURES logic fix?

[Harry Schmalzbauer]

Hello,

just from an isolated view, line 1047 
(https://svnweb.freebsd.org/ports/head/Mk/bsd.port.mk?view=markup&pathrev=529956) 
reads:

if !defined(PORTS_FEATURES) && empty(${PORTS_FEATURES:MFLAVORS})

I guess the negation was swapped, since ${PORTS_FEATURES:MFLAVORS} is 
always empty if ${PORTS_FEATURES} is undefined, is it?

Never looked at PORTS_FEATURES, but what's the meaning if FLAVORS is 
added unconditionally – even if the tautological if statement was fixed, 
it's still unconditionally set…

Thanks,

-harry