[xmonad] Change build directory to ~/.cache/xmonad

[wagnerdm at seas.upenn.edu]

Quoting Joachim Breitner <mail at joachim-breitner.de>:

> Hi,
>
> Am Donnerstag, den 05.07.2012, 10:03 -0700 schrieb
> daniel.trstenjak at gmail.com:
>> Thu Jun  7 15:16:32 CEST 2012  daniel.trstenjak at gmail.com
>>   * Separate source and build directories
>>   The source files are still located in '~/.xmonad'
>>   and the build files and the xmonad binary are now put
>>   into '~/.xmonad_build'.
>
> to avoid namespace pollution, why not ~/.xmonad/build?

If you look a tad further down the patch list, you'll see it ends in  
~/.cache/xmonad, presumably following the XDG spec, which was designed  
exactly to avoid namespace pollution.

~d