Fix building of libmkc documentation on RTD

Author: RedFantom

docs/doxygen.conf

@@ -770,7 +770,7 @@ WARN_LOGFILE           =
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = ../libmk
+INPUT                  = ../libmk ../libmkc
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses