private static boolean isEquivalent(ExternalLocation extLoc1, ExternalLocation extLoc2) {
		if (extLoc1 == null && extLoc2 == null) {
			return true;
		}
		if (extLoc1 == null || extLoc2 == null) {
			return false;
		}

		return extLoc1.isEquivalent(extLoc2);

	}
Compares reference from program1 with reference from program2 to see if they are equivalent.
@param p1 program1
@param p2 program2
@param ref1 program1 reference
@param ref2 program2 reference
@return true if they are equivalent
Ghidra/Features/Base/src/main/java/ghidra/program/util/ProgramDiff.java