Checking dependencies with Distribution

[Maurí­cio CA]

Hi,

Can you help me understand how to check C library dependencies
using Distribution.*?

So far, reading Setup.hs from HDBC-mysql gave me a quick start. I
believe what I need to do is to write a 'preConf' user hook.

This preConf would probably mimic the behavior of autoconf macros
provided by the library. Say, if that macro opens an include
file and checks a string to confirm the version, that is what my
preConf should do.

But then I'm lost. Although my preConf probably doesn't need to
add any information to the build process, I can't find how to
actually break it if the proper version wasn't found, or how to
emit a message saying "you need a newer version of library X".

Thanks,
Maurício