prevent output from filesystem check

CMakeLists.txt

@@ -478,7 +478,7 @@ try_compile( WALBERLA_USE_STD_FILESYSTEM "${CMAKE_CURRENT_BINARY_DIR}" "${CMAKE_
              COMPILE_DEFINITIONS -DWALBERLA_USE_STD_FILESYSTEM COPY_FILE "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" )
 if( WALBERLA_USE_STD_FILESYSTEM )
   # detect https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90050 by checking whether it segfaults
-  execute_process( COMMAND "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" RESULT_VARIABLE WALBERLA_STD_FILESYSTEM_WORKS )
+  execute_process( COMMAND "${CMAKE_CURRENT_BINARY_DIR}/TestStdFilesystem" OUTPUT_QUIET RESULT_VARIABLE WALBERLA_STD_FILESYSTEM_WORKS )
 endif()
 if( WALBERLA_USE_STD_FILESYSTEM AND WALBERLA_STD_FILESYSTEM_WORKS EQUAL 0 )
    message( STATUS "Found std::filesystem")