git: ac9a064cb179..c76260f306a7 - vendor/llvm-project/release-19.x - vendor branch updated

[Dimitry Andric]

The branch vendor/llvm-project/release-19.x has been updated by dim:

URL: https://cgit.FreeBSD.org/src/log/?id=ac9a064cb179..c76260f306a7

c76260f306a7 Vendor import of llvm-project branch release/19.x 
llvmorg-19.1.0-rc1-0-ga4902a36d5c2.