Bug#1080464: Fix feature check for clang-19+

[Drew Parsons]

Source: xtensor
Followup-For: Bug #1080464
X-Debbugs-Cc: Matthias Klose <d...@debian.org>

> Fix feature check for clang-19+, taken from upstream.

Hi Matthias, could you provide a link to the upstream patch?

Drew