git: c54ffb070c1a - stable/15 - .github: Update to use llvm 15

The branch stable/15 has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=c54ffb070c1aa072e4eed86548aef76887ef888d

commit c54ffb070c1aa072e4eed86548aef76887ef888d
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2025-09-11 07:22:38 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2026-10-17 15:36:08 +0000

    .github: Update to use llvm 15
    
    This is the latest supported version in Ubuntu 22.04
    
    Reviewed by:    vexeduxr, imp, emaste
    Sponsored by:   Arm Ltd
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/1862
    
    (cherry picked from commit cf583997282f962d9e8bf478667d5087f7c1f2da)
---
 .github/workflows/cross-bootstrap-tools.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/cross-bootstrap-tools.yml b/.github/workflows/cross-bootstrap-tools.yml
index 96cc534472ea..d8893a6ecff8 100644
--- a/.github/workflows/cross-bootstrap-tools.yml
+++ b/.github/workflows/cross-bootstrap-tools.yml
@@ -22,9 +22,9 @@ jobs:
         include:
           # TODO: both Ubuntu and macOS have bmake packages, we should try them instead of bootstrapping our own copy.
           - os: ubuntu-22.04
-            compiler: clang-14
-            cross-bindir: /usr/lib/llvm-14/bin
-            pkgs: bmake libarchive-dev clang-14 lld-14
+            compiler: clang-15
+            cross-bindir: /usr/lib/llvm-15/bin
+            pkgs: bmake libarchive-dev clang-15 lld-15
           - os: ubuntu-24.04
             compiler: clang-18
             cross-bindir: /usr/lib/llvm-18/bin