darcs patch: Warn if C dependencies not found (kind of fixes #262)

[Duncan Coutts]

On Mon, 2009-01-26 at 21:03 +0200, gleb.alexeev at gmail.com wrote:
> Mon Jan 26 20:58:32 EET 2009  gleb.alexeev at gmail.com
>   * Warn if C dependencies not found (kind of fixes #262)
>   
>   This is just a basic check - generate a sample program and check if it compiles and links with relevant flags. Error messages (warning messages, 
>   actually) could use some improvement.

Great! Thanks for working on this, it's the last big ticket for the
1.6.0.2 release (which I hope we'll have in ghc-6.10.2).

I'll try this out and get back to you.

Duncan