Index: trunk/Mars/cmake/rootlogon.C.in
===================================================================
--- trunk/Mars/cmake/rootlogon.C.in	(revision 19749)
+++ trunk/Mars/cmake/rootlogon.C.in	(revision 19750)
@@ -44,5 +44,7 @@
 #include <iomanip>
 
-#if defined(ROOT_VERSION_CODE)
+#cmakedefine ROOT_VERSION_AVAILABLE "@ROOT_VERSION_MAJOR@"
+
+#if defined(ROOT_VERSION_CODE) && defined(ROOT_VERSION_AVAILABLE)
 #if ROOT_VERSION_CODE != ROOT_VERSION(${ROOT_VERSION_MAJOR},${ROOT_VERSION_MINOR},${ROOT_VERSION_PATCH})
 #error Started ROOT version does not match ROOT version linked with libmars.so