add a tmate debugging session

Author: mattip

.github/workflows/posix.yml

@@ -102,6 +102,12 @@ jobs:
           build_lib "$PLAT" "$INTERFACE64" "0"
         fi
 
+    - name: Setup tmate session
+      if: ${{ failure() }}
+      uses: mxschmitt/action-tmate@v3
+      with:
+        limit-access-to-actor: true
+
     - name: Build and test wheel
       run: |
         if [[ "$NIGHTLY" = "true" ]]; then

tools/build_steps.sh

@@ -170,7 +170,7 @@ function do_build_lib {
     CFLAGS="$CFLAGS -fvisibility=protected -Wno-uninitialized" \
     make BUFFERSIZE=20 DYNAMIC_ARCH=1 \
         USE_OPENMP=0 NUM_THREADS=64 \
-        BINARY=$bitness $interface_flags $target_flags
+        BINARY=$bitness $interface_flags $target_flags > /dev/null
     make PREFIX=$BUILD_PREFIX $interface_flags install
     popd
     stop_spinner