void createExternalLabel(MergeProgram mergeProgram, String[] path, String memoryAddress,
			DataType dt, SourceType sourceType) {

		int nameIndex = path.length - 1;
		Library currentLibrary = null;
		for (int i = 0; i < nameIndex; i++) {
			currentLibrary = mergeProgram.createExternalLibrary(path[i], sourceType);
		}

		mergeProgram.addExternalLocation(currentLibrary, path[nameIndex], memoryAddress, dt,
			sourceType);
	}
The external function merger only detects and merges source differences when a name
difference is being merged.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/merge/listing/ExternalMergerAddTest.java