diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4a891f79d8..52f286ebfe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -48,7 +48,7 @@ else()
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 endif()
-if(NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+if(NOT "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xMSVC")
   set(disable_flags "-Wno-unused-function -Wno-unused-parameter")
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${disable_flags}")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${disable_flags} -Wno-reorder")