private boolean isExternalUserDefined(Program pgm, String externalName) {
		SymbolTable symTab = pgm.getSymbolTable();
		Symbol s = symTab.getLibrarySymbol(externalName);
		if (s != null) {
			return (s.getSource() == SourceType.USER_DEFINED);
		}
		return false;
	}
Gets symbol ID groups for each Library symbol that is new in the My program
(symbol wasn't in the Original program).
<br> Note: This method excludes any new Library symbols in Original whose matching Result ID
has already been placed in the resultIDsInAGroup set. Otherwise, each ID group that has a
Result ID will add it to the resultIDsInAGroup set.
@return the ID groups for new Library symbols in the My program.
Ghidra/Features/Base/src/main/java/ghidra/app/merge/listing/ExternalProgramMerger.java