git: b1c73532ee89..312c0ed19cc5 - vendor/llvm-project/main - vendor branch updated

From: Dimitry Andric <dim_at_FreeBSD.org>
Date: Sun, 17 Dec 2023 20:42:01 UTC
The branch vendor/llvm-project/main has been updated by dim:

URL: https://cgit.FreeBSD.org/src/log/?id=b1c73532ee89..312c0ed19cc5

312c0ed19cc5 Vendor import of llvm-project main llvmorg-18-init-15088-gd14ee76181fb.