adding CURLM_CALL_MULTI_SOCKET that's just the same as CURLM_CALL_MULTI_PERFORM

include/curl/multi.h

@@ -96,7 +96,8 @@ typedef int curl_socket_t;
 #endif /* curl_socket_typedef */
 
 typedef enum {
-  CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() soon */
+  CURLM_CALL_MULTI_PERFORM = -1, /* please call curl_multi_perform() or
+                                    curl_multi_socket*() soon */
   CURLM_OK,
   CURLM_BAD_HANDLE,      /* the passed-in handle is not a valid CURLM handle */
   CURLM_BAD_EASY_HANDLE, /* an easy handle was not good/valid */
@@ -107,6 +108,11 @@ typedef enum {
   CURLM_LAST
 } CURLMcode;
 
+/* just to make code nicer when using curl_multi_socket() you can now check
+   for CURLM_CALL_MULTI_SOCKET too in the same style it works for
+   curl_multi_perform() and CURLM_CALL_MULTI_PERFORM */
+#define CURLM_CALL_MULTI_SOCKET CURLM_CALL_MULTI_PERFORM
+
 typedef enum {
   CURLMSG_NONE, /* first, not used */
   CURLMSG_DONE, /* This easy handle has completed. 'result' contains