diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab3acf4b..148b1209 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,16 +33,27 @@ macro(register_lego1_target __target)
   list(APPEND lego1_targets ${__target})
 endmacro()
 
-function(check_cxx_has_option VAR OPTION)
+function(add_cxx_warning WARNING)
+    if(ISLE_WERROR)
+        set(compiler_option "-Werror=${WARNING}")
+    else()
+        set(compiler_option "-W${WARNING}")
+    endif()
+    string(MAKE_C_IDENTIFIER "COMPILER_SUPPORTS${compiler_option}" varname)
+
     cmake_push_check_state(RESET)
-    set(CMAKE_REQUIRED_FLAGS "${OPTION} ")
+    set(CMAKE_REQUIRED_FLAGS "${compiler_option} ")
     if(MSVC)
         string(APPEND CMAKE_REQUIRED_FLAGS "/WX")
     else()
         string(APPEND CMAKE_REQUIRED_FLAGS "-Werror")
     endif()
-    check_cxx_source_compiles("int main() { return 0; }" ${VAR})
+    check_cxx_source_compiles("int main() { return 0; }" ${varname})
     cmake_pop_check_state()
+
+    if(${varname})
+        add_compile_options(${compiler_option})
+    endif()
 endfunction()
 
 message(STATUS "MSVC for decompilation: ${MSVC_FOR_DECOMP}")
@@ -61,10 +72,7 @@ if(ISLE_WERROR)
     endif()
 endif()
 
-check_cxx_has_option(COMPILER_SUPPORTS_Wparentheses -Wparentheses)
-if(COMPILER_SUPPORTS_Wparentheses)
-    add_compile_options(-Wparentheses)
-endif()
+add_cxx_warning(parentheses)
 
 add_library(DirectX5::DirectX5 INTERFACE IMPORTED)
 target_include_directories(DirectX5::DirectX5 INTERFACE "${CMAKE_SOURCE_DIR}/3rdparty/dx5/inc")