Fixed signed/unsigned convertion errors in Salford-C.

#ifdef around WSAEDISCON in strerror.c.

lib/formdata.c

@@ -1279,7 +1279,7 @@ static size_t readfromfile(struct Form *form, char *buffer, size_t size)
     /* this file hasn't yet been opened */
     form->fp = fopen(form->data->line, "rb"); /* b is for binary */
     if(!form->fp)
-      return -1; /* failure */
+      return (size_t)-1; /* failure */
   }
   nread = fread(buffer, 1, size, form->fp);
 

lib/multi.c

@@ -780,7 +780,7 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi,
           /* if we failed anywhere, we must clean up the secondary socket if
              it was used */
           sclose(easy->easy_conn->sock[SECONDARYSOCKET]);
-          easy->easy_conn->sock[SECONDARYSOCKET]=-1;
+          easy->easy_conn->sock[SECONDARYSOCKET] = CURL_SOCKET_BAD;
         }
         Curl_posttransfer(easy->easy_handle);
         Curl_done(&easy->easy_conn, easy->result);

lib/select.c

@@ -131,7 +131,7 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
   timeout.tv_usec = (timeout_ms % 1000) * 1000;
 
   FD_ZERO(&fds_err);
-  maxfd = -1;
+  maxfd = (curl_socket_t)-1;
 
   FD_ZERO(&fds_read);
   if (readfd != CURL_SOCKET_BAD) {
@@ -206,7 +206,7 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
   FD_ZERO(&fds_read);
   FD_ZERO(&fds_write);
   FD_ZERO(&fds_err);
-  maxfd = -1;
+  maxfd = (curl_socket_t)-1;
 
   for (i = 0; i < nfds; i++) {
     if (ufds[i].fd == CURL_SOCKET_BAD)

lib/strerror.c

@@ -519,10 +519,11 @@ get_winsock_error (int err, char *buf, size_t len)
   case WSAEREMOTE:
     p = "Remote error";
     break;
+#ifdef WSAEDISCON  /* missing in SalfordC! */
   case WSAEDISCON:
     p = "Disconnected";
     break;
-
+#endif
     /* Extended Winsock errors */
   case WSASYSNOTREADY:
     p = "Winsock library is not ready";