support --enable-debug to switch on picky compiler options

and the original ares installed in the same lib dir.

response reading function

make this better on more systems.

utility

be backwards compatible with older libcurls just fine.

NOTE that this breaks ares-compatibility, we have now officially taken the
turn into the c-ares path. We will now officially depend on c-ares for asynch
name resolves.

This breaks the API and ABI with the existing ares library. We hereby require
the upcoming c-ares 1.0 for asynch name resolves!

as well, and when failing and not getting a timeout we now include the
error message ares can provide us with.

this allows the HTTP code to *not* return a failure just because no data
has been received from the server

Dirk Manske, but modified by me.

the search path since we want the build-version rather than the one in the
source dir

Vanem

header using -H

so that the automatic testing hosts will test these changes over the weekend.