6289479 libresolv2 clean up and alignment with libbind.6.0

PSARC 2007/129 thr_keycreate_once
6513516 double checked locking code needs a memory barrier

6300853 libresolv net_data_init should not increment once until it is done initializing
6527020 libresolv does not handle mutexes correctly

OpenSolaris Launch