Revert "Merge upstream"

This reverts commit c58a50f880, reversing
changes made to a1c3c98773.

.github/actions/setup-build-env/action.yml

@@ -8,7 +8,7 @@ runs:
       shell: bash
       run: |
         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 libbz2-dev libnsl-dev libdwarf-dev libelf-dev elfutils libdw-dev
+        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 libnsl-dev libbz2-dev libdwarf-dev libelf-dev elfutils libdw-dev
 
     - name: Install macOS Dependencies
       if: runner.os == 'macOS'

.github/workflows/test-compile.yml

@@ -30,15 +30,18 @@ jobs:
           - ubuntu-latest
         compiler:
           # oldest supported
-          - 'clang-10'
+          - 'clang-14'
           - 'gcc-10'
           # newest, make sure to update maximum standard step to match
-          - 'clang-19'
+          - 'clang-18'
           - 'gcc-13'
         include:
           # macOS
           - os: macos-13
             compiler: 'clang'
+          # oldest clang not available on ubuntu-latest
+          - os: ubuntu-20.04
+            compiler: 'clang-10'
       fail-fast: false
     steps:
       - name: Checkout Yosys
@@ -69,7 +72,7 @@ jobs:
 
       # maximum standard, only on newest compilers
       - name: Build C++20
-        if: ${{ matrix.compiler == 'clang-19' || matrix.compiler == 'gcc-13' }}
+        if: ${{ matrix.compiler == 'clang-18' || matrix.compiler == 'gcc-13' }}
         shell: bash
         run: |
           make config-$CC_SHORT