diff --git a/development/cmake/CMakeLists.txt b/development/cmake/CMakeLists.txt
index dc05731c52..92d0bb848f 100644
--- a/development/cmake/CMakeLists.txt
+++ b/development/cmake/CMakeLists.txt
@@ -232,7 +232,7 @@ if(NOT MSVC)
 	if(NOT LYX_QUIET)
 		set(CMAKE_VERBOSE_MAKEFILE ON)
 	endif()
-	set(LYX_CXX_FLAGS -Wall -Wunused-parameter)
+	set(LYX_CXX_FLAGS "-Wall -Wunused-parameter")
 	if(LYX_STDLIB_DEBUG)
 		set(LYX_CXX_FLAGS "${LYX_CXX_FLAGS} -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC")
 	endif()