Windows: the loop's socket results in the type the socket calls return

ssize_t does not exist under MSVC, and the socket function table
already spells its send and recv results int there and ssize_t
elsewhere. That type is now named SOCKRET, beside SASIZETYPE, and the
event loop's copies of it use the name, so the MSVC build compiles
again.

src/mainloop.c

@@ -555,7 +555,7 @@ static void cbfail(struct cbmap *m, int side, int writing){
 /* Statistics of what went through a way, as sockmap() counts them, and
    the bandwidth limits' pause: the client's data once written to the
    server, the server's once read. A read counts for the grace. */
-static void cbcount(struct cbmap *m, struct cbway *w, int written, ssize_t n){
+static void cbcount(struct cbmap *m, struct cbway *w, int written, SOCKRET n){
 	struct clientparam *param = m->param;
 	int sl = 0;
 
@@ -603,7 +603,7 @@ static int cbway(struct cbmap *m, struct cbway *w){
 	unsigned char *buf;
 	unsigned *inbuf, *offset, size;
 	uint64_t inb, room;
-	ssize_t n;
+	SOCKRET n;
 
 	if(!w->left) return 0;
 	cbbuf(param, w->src, &buf, &inbuf, &offset, &size);

src/proxy.h

@@ -62,6 +62,7 @@
 #include <io.h>
 #include <process.h>
 #define SASIZETYPE int
+#define SOCKRET int		/* what a socket call returns: moved bytes or -1 */
 #define SHUT_RDWR SD_BOTH
 #define SHUT_WR SD_SEND
 #define SHUT_RD SD_RECEIVE

src/structures.h

@@ -35,6 +35,7 @@ extern "C" {
 #include <net/if.h>
 #endif
 #define SASIZETYPE socklen_t
+#define SOCKRET ssize_t		/* what a socket call returns: moved bytes or -1 */
 #define SOCKET int
 #define INVALID_SOCKET  (-1)
 #define _3proxy_mutex_t pthread_mutex_t