[getdns-api] Capability and version checking

[Phil Pennock]

On 2013-01-29 at 07:45 -0800, Paul Hoffman wrote:
> Would the following match what you are thinking?
> 
> #define GETDNS_COMPILATION_COMMENT The API implementation should fill in something here, and change it each time the API is compiled.

Changed each time the _API_ is compiled, but not the client "compiled
against" the API, is fine.  Better if the text can explicitly suggest
that version information is appropriate here, so that it's more than
just a compilation date which doesn't tell you much that's useful.  This
is more relevant since you're bucking what little convention exists
here.

The only extant example which uses that naming is MySQL, where the
_COMMENT explicitly does _not_ include the version information, you have
MYSQL_SERVER_VERSION and MYSQL_COMPILATION_COMMENT:

#define MYSQL_SERVER_VERSION            "5.5.10"
#define MYSQL_COMPILATION_COMMENT       "Source distribution"

Thanks,
-Phil