enable support for passing the ICEAUTHORITY shell variable to define where to create the ice auth file
diff -r -u xfce4-session-4.4.3.orig/xfce4-session/main.c xfce4-session-4.4.3/xfce4-session/main.c
--- xfce4-session-4.4.3.orig/xfce4-session/main.c	2009-01-23 20:25:08 -0600
+++ xfce4-session-4.4.3/xfce4-session/main.c	2009-01-24 00:56:16 -0600
@@ -67,7 +67,7 @@
 {
   const gchar *lang;
   const gchar *sm;
-  gchar       *authfile;
+  gchar       *authfile = NULL;
   int          fd;
 
   /* check that no other session manager is running */  
@@ -94,7 +94,11 @@
     }
 
   /* check access to $HOME/.ICEauthority */
-  authfile = xfce_get_homefile (".ICEauthority", NULL);
+  authfile = g_getenv ("ICEAUTHORITY");
+
+  if (authfile == NULL)
+  	authfile = xfce_get_homefile (".ICEauthority", NULL);
+
   fd = open (authfile, O_RDWR | O_CREAT, 0600);
   if (fd < 0)
     {