host-utils: Drop workaround for buggy Apple Clang __builtin_subcll()

host-utils: Drop workaround for buggy Apple Clang __builtin_subcll()

In commit b0438861efe ("host-utils: Avoid using __builtin_subcll on
buggy versions of Apple Clang") we added a workaround for a bug in
Apple Clang 14 where its __builtin_subcll() implementation was wrong.
This bug was only present in Apple Clang 14, not in upstream clang,
and is not present in Apple Clang versions 15 and newer.

Since commit 4e035201 we have required at least Apple Clang 15, so we
no longer build with the buggy versions.  We can therefore drop the
workaround. This is effectively a revert of b0438861efe.

This should not be backported to stable branches, which may still
need to support Apple Clang 14.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3030
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250714145033.1908788-1-peter.maydell@linaro.org