ControlFlashConfigSet sets
(writes) the flash configuration of a Control object (control),
using data from the structure pointed to by config,
and also using data from the implementation-specific structure
pointed to by external (if external
is not NULL).
The Control's flash configuration information in external
is in addition to the Control's flash configuration information
in config, i.e., the flash configuration information in config
and in external is not the same information. Note
that config or external can be NULL
(but not both NULL).