src/main/java/com/basistech/tclre/Locale.java
static UnicodeSet allcases(int c) {
        UnicodeSet set = new UnicodeSet();
        set.add(c);
        set.closeOver(UnicodeSet.ADD_CASE_MAPPINGS);
        return set;
    }
static UnicodeSet allcases(int c) {
        UnicodeSet set = new UnicodeSet();
        set.add(c);
        set.closeOver(UnicodeSet.ADD_CASE_MAPPINGS);
        return set;
    }
allcases - supply cvec for all case counterparts of a chr (including itself)
This is a shortcut, preferably an efficient one, for simple characters;
messy cases are done via range().