patch applied (packages/filepath): jiggle with cpp magic

[Simon Peyton-Jones]

| >   * jiggle with cpp magic
| >   The use of cpp macros _as well as_ conditionals to define which
| >   modules to import is horrible.  More to the point, it breaks hmake,
| >   which (for good reason) only supports conditionals not macros.  Since
| >   the conditional-only mechanism is equal in power, there's no reason to
| >   use the more general macro facility.
| >
| >     M ./System/FilePath.hs -4 +4
|
| The current state of things is not much better: Due to the CPP trickery, the
| GHC build system misses dependecies on the internal module. I can understand
| the motivation behind all this preprocessing magic, but we have to solve this
| differently somehow...

We're all ears!

Simon