Use a 64-bit type to hold sockets on win64.

On win64, sockets are of type UINT_PTR; on win32 they're u_int;
elsewhere they're int.  The correct windows way to check a socket for
being set is to compare it with INVALID_SOCKET; elsewhere you see if
it is negative.

On Libevent 2, all callbacks take sockets as evutil_socket_t; we've
been passing them int.

This patch should fix compilation and correctness when built for
64-bit windows.  Fixes bug 3270.

src/or/cpuworker.c

@@ -226,8 +226,8 @@ cpuworker_main(void *data)
 {
   char question[ONIONSKIN_CHALLENGE_LEN];
   uint8_t question_type;
-  int *fdarray = data;
-  int fd;
+  tor_socket_t *fdarray = data;
+  tor_socket_t fd;
 
   /* variables for onion processing */
   char keys[CPATH_KEY_MATERIAL_LEN];
@@ -317,12 +317,12 @@ cpuworker_main(void *data)
 static int
 spawn_cpuworker(void)
 {
-  int *fdarray;
-  int fd;
+  tor_socket_t *fdarray;
+  tor_socket_t fd;
   connection_t *conn;
   int err;
 
-  fdarray = tor_malloc(sizeof(int)*2);
+  fdarray = tor_malloc(sizeof(tor_socket_t)*2);
   if ((err = tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fdarray)) < 0) {
     log_warn(LD_NET, "Couldn't construct socketpair for cpuworker: %s",
              tor_socket_strerror(-err));