FcPatternAdd − Add a value to a pattern
FcBool FcPatternAdd (FcPattern *p, const char *object, FcValue value, FcBool append);
Adds a single value to the list of values associated with the property named ‘object. If ‘append is FcTrue, the value is added at the end of any existing list, otherwise it is inserted at the beginning. ‘value’ is saved (with FcValueSave) when inserted into the pattern so that the library retains no reference to any application-supplied data structure.