Instead of hardcoding the wx version in CMakeCache.txt, we pass it as
-DWX_VERSION from debian/rules.

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -88,7 +88,7 @@ INCLUDE(CPack)
 ################################################################################
 SET(WX_DEBUG NO CACHE BOOL "Use the debug build of wxWidgets?")
 SET(WX_STATIC ${STATIC_BUILD})
-SET(WX_VERSION "2.8")
+#SET(WX_VERSION "2.8")
 SET(WX_UNICODE YES)
 SET(WX_MODULES "base")
 
