Default prefix for Cabal on Windows

[Brian Smith]

Hi all,

The documentation states in Section 3.1 that the default value of
"prefix" is "/usr/local" on Unix. However, it doesn't specify what the
prefix is on Windows. I found that the default value for prefix is:
    C:\Program Files\<package-name>\<compiler-name>-<compiler-version>.
For example, version 1.0 of a package named "Foo" compiled with GHC
6.5 would have a default prefix of:
    C:\Program Files\Foo\ghc-6.5

I think that a better default value of prefix on Windows would be:
    C:\Program Files\<package-name>-<package-version>
e.g.:
    C:\Program Files\Foo-1.0

In particular, I think it is undesirable to have the name and version
of the compiler embedded in the default prefixes.

Regardless of whether or not it is changed, this would be another good
thing to put into the documentation.

Regards,
Brian