diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 79baf2305..172376e4c 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -35,7 +35,7 @@ jobs:
                 tcl-dev zlib-dev libffi-dev \
                 libdwarf-dev elfutils-dev \
                 python3 python3-dev py3-pip py3-setuptools py3-wheel \
-                git pkgconf ccache
+                git pkgconf cmake
 
               git config --global --add safe.directory /src
               git submodule foreach --recursive git config --global --add safe.directory \$toplevel/\$sm_path
@@ -81,9 +81,11 @@ jobs:
               set -ex
 
               yum install -y tcl-devel zlib-devel libffi-devel \
-                flex gperf ccache patchelf \
+                devtoolset-11 flex gperf patchelf \
                 elfutils-devel elfutils-libelf-devel libdwarf-devel
 
+              source /opt/rh/devtoolset-11/enable
+
               # Build bison >= 3.x from source
               curl -L https://ftp.gnu.org/gnu/bison/bison-3.8.2.tar.gz | tar -xzC /tmp
               cd /tmp/bison-3.8.2 && ./configure && make -j$(nproc) && make install
@@ -137,7 +139,8 @@ jobs:
 
       - name: Install dependencies
         run: |
-          brew install bison flex gperf tcl-tk@8 libffi dwarfutils libelf ccache
+          brew install bison flex gperf tcl-tk@8 libffi dwarfutils libelf ccache llvm
+          echo "$(brew --prefix llvm)/bin" >> $GITHUB_PATH
           pip3 install pybind11 cxxheaderparser setuptools wheel
 
       - name: Build Verific tclmain
@@ -160,6 +163,8 @@ jobs:
           path: dist/*.whl
 
   release:
+    # allow testing outside main branch
+    if: github.ref_name == 'main'
     runs-on: ubuntu-latest
     needs: [build-linux-wheel, build-manylinux-wheel, build-macos-wheel]
     name: Create GitHub releases
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 718b56e35..a5493c313 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -94,7 +94,7 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
 	endif()
 	set(no_abc_options
 		"$<$<AND:$<NOT:$<BOOL:$<TARGET_PROPERTY:YOSYS_IS_ABC>>>,$<CONFIG:Sanitize>>:-fsanitize=${SANITIZE}>"
-		"$<$<NOT:$<BOOL:$<TARGET_PROPERTY:YOSYS_IS_ABC>>>:-Wall;-Wextra;-Werror=unused>"
+		"$<$<NOT:$<BOOL:$<TARGET_PROPERTY:YOSYS_IS_ABC>>>:-Wall;-Wextra;-Werror=unused-variable>"
 	)
 	add_compile_options("${no_abc_options}")
 	add_link_options("${no_abc_options}")