Don't make the event loop spin when connect() returns EINPROGRESS.
Test case:
#include "uv.h"
static void connect_cb(uv_connect_t* req, int status) {
// ...
}
int main() {
uv_tcp_t handle;
uv_connect_t req;
struct sockaddr_in addr;
addr = uv_ip4_addr("8.8.8.8", 1234); // unreachable
uv_tcp_init(uv_default_loop(), &handle);
uv_tcp_connect(&req, (uv_stream_t*)&handle, addr, connect_cb);
uv_run(uv_default_loop()); // busy loops until connection times out
return 0;
}
After EINPROGRESS, there are zero active handles and one active request. That
in turn makes uv__poll_timeout() believe that it should merely poll, not block,
in epoll() / kqueue() / port_getn().
Sidestep that by artificially starting the handle on connect() and stopping it
again once the TCP handshake completes / is rejected / times out.
It's a slightly hacky approach because I don't want to change the ABI of the
stable branch. I'll address it properly in the master branch.
Incidentally fixes a rather obscure bug where uv_tcp_connect() reconnected
and leaked a file descriptor when the handle was already busy connecting,
handle->fd was zero (unlikely) and uv_tcp_connect() got called again.
