With miniupnpc-1.5.20110618 installed I get the following build error:
$ make -f makefile.unix USE_UPNP=0 bitcoind
/usr/include/miniupnpc/miniupnpc.h: In function ‘void ThreadMapPort2(void*)’:
/usr/include/miniupnpc/miniupnpc.h:53: error: too few arguments to function ‘UPNPDev* upnpDiscover(int, const char*, const char*, int, int, int*)’
net.cpp:1071: error: at this point in file
/usr/include/miniupnpc/upnpcommands.h:117: error: too few arguments to function ‘int UPNP_AddPortMapping(const char*, const char*, const char*, const char*, const char*, const char*, const char*, const char*, const char*)’
net.cpp:1085: error: at this point in file