libyang REFACTOR config.h code split

... into compat.h and version.h.
diff --git a/src/tree_schema_helpers.c b/src/tree_schema_helpers.c
index 8500b55..e6f4d3b 100644
--- a/src/tree_schema_helpers.c
+++ b/src/tree_schema_helpers.c
@@ -21,8 +21,8 @@
 #include <string.h>
 #include <time.h>
 
+#include "compat.h"
 #include "common.h"
-#include "config.h"
 #include "context.h"
 #include "hash_table.h"
 #include "log.h"