replace real_transparency option with an autodetect of composite manager.

git-svn-id: http://tint2.googlecode.com/svn/trunk@355 121b4492-b84c-0410-8b4c-0d4edfb3f3cc

src/server.h

@@ -51,6 +51,7 @@ typedef struct Global_atom
 	Atom _NET_CLOSE_WINDOW;
 	Atom UTF8_STRING;
 	Atom _NET_SUPPORTING_WM_CHECK;
+	Atom _NET_WM_CM_S0;
 	Atom _NET_WM_STRUT_PARTIAL;
 	Atom WM_NAME;
 	Atom __SWM_VROOT;