Some more Coverity paranoia.

This ones does require SSIZE_MAX... so let's see what the pipes say...

src/xpdev/sockwrap.c

@@ -189,14 +189,17 @@ off_t sendfilesocket(int sock, int file, off_t *offset, off_t count)
 
 	while(total<count) {
 		rd = read(file, buf, sizeof(buf));
-		if(rd==-1)
+		if (rd < 0)
 			return(-1);
 		if (rd == 0)
 			break;
 		for (i = wr = 0; i < rd; i += wr) {
 			wr = sendsocket(sock,buf+i,rd-i);
-			if(wr>0)
+			if (wr > 0) {
+				if ((SSIZE_MAX - i) < wr)
+					wr = SSIZE_MAX - i;
 				continue;
+			}
 			if (wr == SOCKET_ERROR && SOCKET_ERRNO == EWOULDBLOCK) {
 				wr = 0;
 				SLEEP(1);