public static String getLanguageExternalNameValue(Language lang, String name)
			throws IOException {
		LanguageDescription langDesc = lang.getLanguageDescription();
		if (!(langDesc instanceof SleighLanguageDescription)) {
			throw new IOException("Not a Sleigh Language: " + lang.getLanguageID());
		}
		List<String> values = langDesc.getExternalNames(name);
		if (values == null || values.isEmpty()) {
			return null;
		}
		if (values.size() > 1) {
			throw new IOException(
				String.format("Multiple external name values for %s found in language %s", name,
					lang.getLanguageID()));
		}
		return values.get(0);
	}
Returns a value specified in a {@link Language} definition via a
<pre>&lt;external_name tool="<b>name</b>" name="<b>value</b>"/&gt;</pre>
entry.

@param lang {@link Language} to query
@param name name of the value
@return String value
@throws IOException
Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf/DWARFUtil.java