Bump clang from v14 to v15.

Dockerfile-ubuntu2204

     apt-get -y install vim gdb strace patch && \
     \
     apt update -y && \
-    apt-get install -y clang-14 clang-tidy-14 libclang-14-dev clangd-14 lldb-14 lld-14 clangd-14 && \
-    apt-get install -y libc++-14-dev libc++-14-dev clang-format-14 && \
+    apt-get install -y clang-15 clang-tidy-15 libclang-15-dev clangd-15 lldb-15 lld-15 clangd-15 && \
+    apt-get install -y libc++-15-dev libc++-15-dev clang-format-15 clang-tidy-15 && \
     \
     rm -rf /var/lib/apt/lists/*
 

switch-to-latest-clang

 set +e
 set -o pipefail
 
-update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-14 40 > /tmp/.switch-to-clang.stdout
-update-alternatives --install /usr/bin/cc cc /usr/bin/clang-14 40 >>  /tmp/.switch-to-clang.stdout
-update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-14 40 >>  /tmp/.switch-to-clang.stdout
-update-alternatives --install /usr/bin/clang clang /usr/bin/clang-14 40 >>  /tmp/.switch-to-clang.stdout
-update-alternatives --install /usr/bin/ld ld /usr/bin/ld.lld-14 40 >>  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/c++ c++ /usr/bin/clang++-15 40 > /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/cc cc /usr/bin/clang-15 40 >>  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-15 40 >>  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/clang clang /usr/bin/clang-15 40 >>  /tmp/.switch-to-clang.stdout
+update-alternatives --install /usr/bin/ld ld /usr/bin/ld.lld-15 40 >>  /tmp/.switch-to-clang.stdout
 
 echo compiler set to: $(readlink /etc/alternatives/c++)