[ci] Add a clang/libc++ builders for unix

[vgvassilev]

[ro4i7]

Hello @parth-07 @vgvassilev

To build script for a Unix-based system using Clang and libc++:

#!/bin/bash
export CC=/usr/bin/clang
export CXX=/usr/bin/clang++
export CXXFLAGS="-stdlib=libc++"
mkdir build && cd build
cmake ..
make -j4

This script sets the environment variables for the Clang compiler and the C++ standard library to be used during the build process. It then creates a build directory, runs CMake to configure the project, and builds the project using the make command with 4 parallel jobs.

Once the build script is set up, then configure our CI tool to execute this script on the virtual machine for each new commit or pull request. This will ensure that the project is continuously built and tested with the Clang compiler and libc++ library on a Unix system.