build: updated to new clang and other fixes

* don't save macros from external files
* fixed macro and include saving duplicates
* added NODE_UNDEFINED_MACRO

TIL = You need to cut a 1kg cake about 85 times in half until you have a piece with only a single atom.

src/lib/data/parser/cxx/ASTBodyVisitor.cpp

@@ -25,7 +25,7 @@ void ASTBodyVisitor::VisitStmt(clang::Stmt* stmt)
 
 void ASTBodyVisitor::VisitChildren(clang::Stmt* stmt)
 {
-	for (clang::Stmt::child_range it = stmt->children(); it; it++)
+	for (clang::Stmt::child_iterator it = stmt->child_begin(); it != stmt->child_end(); it++)
 	{
 		if (*it)
 		{