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.