diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6751baf0b0..061b8fd741 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,7 +68,7 @@ set(CMAKE_EXE_LINKER_FLAGS_COVERAGE
 mark_as_advanced(CMAKE_CXX_FLAGS_COVERAGE CMAKE_C_FLAGS_COVERAGE CMAKE_EXE_LINKER_FLAGS_COVERAGE)
 
 
-set(ECL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} CACHE string "ECL source location" FORCE)
+set(ECL_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} CACHE STRING "ECL source location" FORCE)
 
 if(CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
 	# ECL standalone build