Build correctly on modern GHC and better error message upon common build failure

[Peaker]

If system lacks "wx-config" in $PATH, then currently the Setup.hs in wxc will just fail silently, swallowing errors. I got: "Setup: failed" which is confusing and frustrating. I added a small patch to log an error about this to make the failure much more self-evident (message about failed invocation of wx-config).

Additionally, wxdirect and wxcore had overly restrictive dependency constraints on time/containers.

Additionally, wxdirect generated FFI declarations that depend on Foreign.C.Types without explicitly importing their data constructors, which is no longer allowed. Similarly, wxcore had such code. Added the necessary imports.