The ifdef for USE_PNP below evals to "true" because it's defined to zero, thereby erroneously enabling UPNP even when it's initialized to zero, which is probably not what's desired. Commenting out the variable makes it not try to build UPNP support by default.
make USE_PNP=1 reenables it nicely.
(I assume the =0 was meant to default it to off?)
No upnp built: USE_UPNP= upnp built but disabled by default: USE_UPNP=0 upnp built and enabled bt default: USE_UPNP=1
Please read build-unix.txt, it explains this.
Is UPNP enabled the intended default behavior?
Built in, but disabled by default ie USE_UPNP=0, which is the intended default.
"USE_UPNP= no UPnP support, miniupnp not required; USE_UPNP=0 (the default) UPnP support turned off by default at runtime; USE_UPNP=1 UPnP support turned on by default at runtime." -from build-unix.txt
ahh, it's also the flag for the default runtime setting, didn't realize that.