[Bug c++/60304] Including <atomic> disables -Wconversion-null

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60304

--- Comment #11 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Ah I see, then Dodji finally has the testcase he was looking for ;) Well, an
equivalent one not using stdbool, which Jon is going to patch. Over the next
week I will be mostly offline, unfortunately, please make sure Dodji sees it!