github actions: Test on several gcc and clang versions on Linux.

Fixes #2776.

.github/workflows/test.yml

@@ -6,9 +6,22 @@ jobs:
   test:
     strategy:
       matrix:
-        runner:
-          - ubuntu-20.04
-          - macOS-10.15
+        include:
+          - runner: ubuntu-20.04
+            config: clang
+            cc: clang
+          - runner: ubuntu-20.04
+            config: gcc
+            cc: gcc
+          - runner: ubuntu-18.04
+            config: gcc
+            cc: gcc-4.8
+          - runner: ubuntu-18.04
+            config: clang
+            cc: clang-3.9
+          - runner: macOS-10.15
+            config: clang
+            cc: clang
     runs-on: ${{ matrix.runner }}
     steps:
 
@@ -20,6 +33,16 @@ jobs:
         sudo apt-get update
         sudo apt-get install g++ gperf build-essential bison flex libreadline-dev gawk tcl-dev libffi-dev git graphviz xdot pkg-config python python3 libboost-system-dev libboost-python-dev libboost-filesystem-dev zlib1g-dev
 
+    - name: Install gcc-4.8
+      if: matrix.cc == 'gcc-4.8'
+      run: |
+        sudo apt-get install g++-4.8
+
+    - name: Install clang-3.9
+      if: matrix.cc == 'clang-3.9'
+      run: |
+        sudo apt-get install clang-3.9
+
     - name: Install dependencies (macOS)
       if: runner.os == 'macOS'
       run: |
@@ -45,7 +68,7 @@ jobs:
       uses: actions/cache@v2
       with:
         path: iverilog-bin
-        key: ${{ runner.os }}-${{ hashFiles('iverilog/.git/refs/heads/master') }}
+        key: ${{ matrix.runner }}-${{ hashFiles('iverilog/.git/refs/heads/master') }}
 
     - name: Build iverilog
       if: steps.cache-iverilog.outputs.cache-hit != 'true'
@@ -59,8 +82,10 @@ jobs:
 
     - name: Build yosys
       run: |
-        make -j${{ env.procs }}
+        ${{ matrix.cc }} --version
+        make config-${{ matrix.config }}
+        make -j${{ env.procs }} CC=${{ matrix.cc }} CXX=${{ matrix.cc }} LD=${{ matrix.cc }}
 
     - name: Run tests
       run: |
-        PATH=$PWD/iverilog-bin/bin:$PATH make -j${{ env.procs }} test
+        PATH=$PWD/iverilog-bin/bin:$PATH make -j${{ env.procs }} test CC=${{ matrix.cc }} CXX=${{ matrix.cc }} LD=${{ matrix.cc }}