The first four are asynchronous analogues of PQconnectdb and PQreset -
they allow an application to connect to the DB without blocking on
remote I/O.
The PQsetenv functions perform an environment negotiation with the
server.
Internal to libpq, pqReadReady and pqWriteReady have been made available
across the library (they were previously static functions inside
fe-misc.c). A lot of internal rearrangement has been necessary to
support these changes.
The API documentation has been updated also.
Caveats:
o The Windows code does not default to using non-blocking sockets,
since I have no documentation: Define WIN32_NON_BLOCKING_CONNECTIONS to
do that.