ci: add clang setup to test

Author: KrystalDelusion

.github/workflows/test-linux.yml

@@ -88,7 +88,7 @@ jobs:
         shell: bash
         run: |
           cd build
-          tar -cvf ../build.tar Makefile.conf share/ yosys yosys-*
+          tar -cvf ../build.tar share/ yosys yosys-*
 
       - name: Store build artifact
         if: (matrix.cpp_std == 'c++11') && (matrix.compiler == 'gcc-11')
@@ -113,6 +113,20 @@ jobs:
           sudo apt-get update
           sudo apt-get install gperf build-essential bison flex libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
+      - name: Setup Clang
+        if: runner.os == Linux
+        shell: bash
+        run: |
+          wget https://apt.llvm.org/llvm-snapshot.gpg.key
+          sudo apt-key add llvm-snapshot.gpg.key
+          rm llvm-snapshot.gpg.key
+          sudo apt-add-repository "deb https://apt.llvm.org/${{ matrix.os.name }}/ llvm-toolchain-${{ matrix.os.name }} main"
+          sudo apt-get update
+          CXX=${CC/#clang/clang++}
+          sudo apt-get install $CC $CXX
+          echo "CC=$CC" >> $GITHUB_ENV
+          echo "CXX=$CXX" >> $GITHUB_ENV
+
       - name: Runtime environment
         shell: bash
         env:
@@ -164,4 +178,5 @@ jobs:
       - name: Run tests
         shell: bash
         run: |
+          make -f ../Makefile config-clang
           make -j${{ env.procs }} test TARGETS= EXTRA_TARGETS=