fix compilation logic

Author: andreasbuhr

cmake/FindCoroutines.cmake

@@ -150,17 +150,22 @@ endif()
 
 if(find_final)
     check_include_file_cxx("coroutine" _CXX_COROUTINES_HAVE_HEADER)
+    if(_CXX_COROUTINES_HAVE_HEADER)
+        check_cxx_source_compiles("#include <coroutine> \n typedef std::suspend_never blub; \nint main() {} " _CXX_COROUTINES_FINAL_HEADER_COMPILES)
+        set(_CXX_COROUTINES_HAVE_HEADER ${}_CXX_COROUTINES_FINAL_HEADER_COMPILES})
+    endif()
+
     if(NOT _CXX_COROUTINES_HAVE_HEADER)
         cmake_push_check_state()
         set(CMAKE_REQUIRED_FLAGS "${_CXX_COROUTINES_EXTRA_FLAGS}")
         check_include_file_cxx("coroutine" _CXX_COROUTINES_HAVE_HEADER_WITH_FLAG)
+        if(_CXX_COROUTINES_HAVE_HEADER_WITH_FLAG)
+            check_cxx_source_compiles("#include <coroutine> \n typedef std::suspend_never blub; \nint main() {} " _CXX_COROUTINES_FINAL_HEADER_COMPILES_WITH_FLAG)
+            set(_CXX_COROUTINES_HAVE_HEADER_WITH_FLAG ${_CXX_COROUTINES_FINAL_HEADER_COMPILES_WITH_FLAG})
+        endif()
         set(_CXX_COROUTINES_HAVE_HEADER ${_CXX_COROUTINES_HAVE_HEADER_WITH_FLAG})
         cmake_pop_check_state()
     endif()
-    check_cxx_source_compiles("#include <coroutine> \n typedef std::suspend_never blub; \nint main() {} " _CXX_COROUTINES_FINAL_HEADER_COMPILES)
-    if(NOT _CXX_COROUTINES_FINAL_HEADER_COMPILES)
-        set(_CXX_COROUTINES_HAVE_HEADER FALSE)
-    endif()
     mark_as_advanced(_CXX_COROUTINES_HAVE_HEADER)
     if(_CXX_COROUTINES_HAVE_HEADER)
         # We found the non-experimental header. Don't bother looking for the