It was impossible to build the sources of BitNet.cpp using the latest version of clang and clang++.

We built the sources of BitNet.cpp using clang.
Now, we could not build the sources of it using clan version > 18.
According to the README, we can install clang using the following command.

bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"

However, this command cannot install clang version 18 and libomp.
Threfore, I think we should use the following commands.

sudo apt install -y lsb-release wget software-properties-common gnupg
wget https://apt.llvm.org/llvm.sh
bash llvm.sh 18 all

We can install clang version 18 in this way.

In addition to this, if we build the sources of it on Linux systems, we should set the following env values.

export CC=/usr/bin/clang-18
export CXX=/usr/bin/clang++-18

If you agree with my proposal, would it be okay to add the above content to the README?

Update the README's Linux build prerequisites using the proposed llvm.sh installation commands and the CC/CXX environment variables. First inspect the current Clang installation and build instructions, then verify that the documented commands install Clang 18 and libomp and allow the sources to build on Linux.