public String expandDefine(String defName) {
		// don't worry about macros
		if (isArg(defName)) {
			//System.err.println(defName + " = " + getValue(defName));
			return null;
		}

		// check if this is a numeric expression that could be simplified
		//
		String strValue = getValue(defName);

		ArrayList<String> list = new ArrayList<>();
		list.add(defName);

		String strExpanded = expand(strValue, true, list);
		strValue = strExpanded;

		return strValue;
	}
Given a data type manager, populate defines with constant values as Enums
Ghidra/Features/Base/src/main/java/ghidra/app/util/cparser/CPP/DefineTable.java