Adding missing declspec for windows dll build.

radixcore/stringfunctions.hh

@@ -22,7 +22,7 @@ namespace radix
  * @param c char
  * @return integer
  */
-int ordinal(char c);
+int RADIX_PUBLIC ordinal(char c);
 
 /**
  * @brief itoa converts integer into character
@@ -30,7 +30,7 @@ int ordinal(char c);
  * @return char
  */
 template <typename type = int>
-char itoa(type number);
+char RADIX_PUBLIC itoa(type number);
 
 /**
  * @brief utc_to_time UTC time to