Add a new variable WITH_STATIC_SUPPLICANT to cause wpa_supplicant to be
linked staticly. This allows it to be used from devd at startup. 
Use LIB_DEPENDS instead of BUILD_DEPENDS for the libdnet depend since we
need it to run too. 
My changes differ from the submitted fixes.
Submitted by: Darren Pilgrim <dmp at bitfreak dot org> 
Pawel Worach <pawel dot worach at gmail dot com>