Autotools enables -Wtrampolines and -Wlogical-op for Clang
The Autotools build system enables extra compiler warnings -- which is a good thing -- but it tries to only enable extra flags like
-Wlogical-op for GCC, which is the only compiler that supports these. Unfortunately
$GCC in Autotools just checks for
__GNUC__ which is true for Clang as well.
The result of this is that building with Clang emits repeated warnings about not understanding these two flags. You can see this in the CI macOS Autotools build.