diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 23d662d..068d715 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -29,7 +29,9 @@
     add_test(${data_name}-suite test_suite_${data_name})
 endfunction(add_test_suite)
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-function")
+if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_CLANG)
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-unused-function")
+endif(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_CLANG)
 
 add_test_suite(aes aes.ecb)
 add_test_suite(aes aes.cbc)