Finish wrapping <netdb.h> so that calls go direct and the symbols are all weak

Make the asr API public. Install asr.h to /usr/include.h and manpages.
Include tweaks suggested by mpi@

ok deraadt@

Cleanup and simplify the API to be exposed. Use better names for
structures, functions and defines.

discussed with and ok deraadt@ guenther@

Make some symbols static and prefix all visible symbols with asr_
to prevent collisions with third-party programs.

suggested by sthen@, ok theo@

Add minimal support for _res setup and update.

Change res_init() to initialize the _res structure on first call, and
udpate the global async context if changes were made by the user. All
resolver fu

Add minimal support for _res setup and update.

Change res_init() to initialize the _res structure on first call, and
udpate the global async context if changes were made by the user. All
resolver functions now call res_init() internally.

fixes issue spotted by otto@

show more ...

split asr_resolver.c into different files to overlay the libc/net
resolver implementation.