Redefine wrapper for wsock32.dll and ws2_32.dll.
(std_dll_init): New function.
* autoload.h: Rename LoadDLLinitfunc to LoadDLLinitfuncdef.
Add new defines LoadDLLinitfunc and LoadDLLstdfunc.
* net.cc (wsock_init): Add guard variable handling. Take care
to call WSAStartup only once. Load WSAStartup without using
autoload wrapper to eliminate recursion. Eliminate FIONBIO
and srandom stuff.