meson: use llvm-config instead of cmake to fix linking errors with meson 1.2.1

The cmake path picks a random LLVM in /usr, which happens to be 32-bit LLVM,
which fails to link with 64-bit Mesa. This is a meson, cmake, or LLVM bug.

Acked-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25042>
1 file changed