diff --git a/cmake/compilers.cmake b/cmake/compilers.cmake
index 2381f1f6..eee777d2 100644
--- a/cmake/compilers.cmake
+++ b/cmake/compilers.cmake
@@ -1,15 +1,7 @@
-include(CheckCCompilerFlag)
-
-# --- compiler options
-
-check_c_compiler_flag(-Wall _has_wall)
-if(_has_wall)
-  add_compile_options(-Wall)
+if(MSVC)
+  add_compile_options(/W4)
 else()
-  check_c_compiler_flag(/Wall _has_msvc_wall)
-  if(_has_msvc_wall)
-    add_compile_options(/Wall)
-  endif()
+  add_compile_options(-Wall)
 endif()
 
 # disable nuisance warnings from Visual Studio