--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,7 +12,7 @@
 if("${SEM_VER}" VERSION_GREATER "${TTYD_VERSION}")
     set(TTYD_VERSION "${SEM_VER}")
 endif()
-if(NOT "${GIT_COMMIT}" STREQUAL "")
+if(NOT "${GIT_COMMIT}" STREQUAL "unknown")
     set(TTYD_VERSION "${TTYD_VERSION}-${GIT_COMMIT}")
 endif()