Implementing `flag_count` and `flag_get`

Start with the TODO in example.c and inspect the existing flag API and Flag_Context usage before assessing the proposed flag_count and flag_get functions. Done requires resolving the public Flag_Info shape, value representation, and compatibility implications, which the issue leaves open.

You have the following comment in example.c:

 // TODO: Would be nice to have some sort of mechanism to inspect all the defined flags
 //   Maybe just expose flag_global_context? But I'm afraid that this will make changing
 //   its internal structure in a backward compatible way more difficult...
 //   But the only reason we may want to change it right now is to make the array of the
 //   flags dynamic. Maybe we should just make it dynamic and finally expose the internal
 //   structure for good?

What about implementing functions flag_count and flag_get(i) as a compromise?

I mean, the API could look like:

size_t flag_count(void);
const Flag_Info *flag_get(size_t index);

where Flag_Info is a structure, something like:

typedef struct {
    const char *name;
    Flag_Type   type;
    const char *desc;
    const void *value;  // or provide a separate function to read the current value 
} Flag_Info;

In this case, the Flag_Context stays private, but we can iterate for (size_t i = 0; i < flag_count(); ++i) and collect metadata if needed.
We may also add more fields to Flag_Info, for example, a default value or a field that indicates whether “was this flag provided?”, or something else.

Should I try to implement this?