Defined constants for TCP and UDP, instead of using the characters themselves

includes/easysock.hpp

@@ -18,8 +18,8 @@
 
 /* Constants that can be used in place of characters, when specifying
 the transport layer protocol */
-const char ES_TCP 'T';
-const char ES_UDP 'U';
+const char ES_TCP = 'T';
+const char ES_UDP = 'U';
 
 /* This function takes:
 a layer 3 - network layer - integer, which must be '4' for IPv4