[dwm] patch

Hi,

I just created patch which includes some minor patches, maybe at least
some of them can be included.

it contains these parts:
- reintroducion of union Arg
- join of focusnext and focusprev into one function which use parameter
- reenabling -Os and stripping of build (to save binary size)
- every global/function is static (to save binary size too)
- uses float instead of double
- remove Client->prev which is really not so needed
- replace minax/minay, maxax/maxay with float mina, maxa

Some of these features are more or less POC, for discussion (removing
->prev for example).

diffstat:
 config.def.h | 70 ++++++------
 config.mk | 4
 dwm.c | 342
 ++++++++++++++++++++++++++++-------------------------------
 3 files changed, 205 insertions(+), 211 deletions(-)

-- 
Premysl "Anydot" Hruby, http://www.redrum.cz/