Fix cinnamon-session to work with the new upower, which has deprecated some
interfaces used in cinnamon-session. The patch adds a new test to configure.ac to
check if the upower installed is the old one (<0.99) or the new one. If the new
one is found we have to disable suspend/hibernate because of bad integration with
consolekit.

While here, switch to tar:xz and disable format-nonliteral and
implicit-function-declaration compile errors in the port Makefile instead of
using clang pragmas.


git-svn-id: svn://creme-brulee.marcuscom.com/ports/trunk@19446 df743ca5-7f9a-e211-a948-0013205c9059