diff -Naur a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt	2020-11-21 07:41:58.000000000 -0600
+++ b/CMakeLists.txt	2020-11-21 08:27:00.146401506 -0600
@@ -4,7 +4,7 @@
 
 file(READ "debian/changelog" CHANGELOG)
 string(REGEX MATCH "cherrytree +\\(([0-9]+)\\.([0-9]+)\\.([0-9]+)[-+]" _ ${CHANGELOG})
-set(CT_VERSION ${CMAKE_MATCH_1}.${CMAKE_MATCH_2}.${CMAKE_MATCH_3})
+option(CT_VERSION ${CMAKE_MATCH_1}.${CMAKE_MATCH_2}.${CMAKE_MATCH_3})
 set(CT_VERSION_WINDOWS ${CMAKE_MATCH_1},${CMAKE_MATCH_2},${CMAKE_MATCH_3},0)
 message(STATUS "CT_VERSION = ${CT_VERSION}")