use abigail to verify our api surface is compatible

.github/workflows/checks.yaml

@@ -366,6 +366,19 @@ jobs:
         run: |
           curl -L "$LINK/cargo-c-x86_64-unknown-linux-musl.tar.gz" |
           tar xz -C $HOME/.cargo/bin
+      - name: Install abigail
+        uses: awalsh128/cache-apt-pkgs-action@latest
+        with:
+          packages: libabigail-dev abigail-tools libbz2-dev
+          version: 1.0
+      - name: Store API
+        run: |
+          ldconfig -p | grep "libbz2.so"
+          libbz2_path=$(ldconfig -p | grep "x86_64-linux-gnu/libbz2.so" | awk '{print $4}')
+          libbz2_filename=$(basename "$libbz2_path")
+          echo $libbz2_path
+          abidw $libbz2_path > /tmp/$libbz2_filename.abi
+          echo "LIBBZ2_FILENAME=$libbz2_filename" >> $GITHUB_ENV
       - name: build with and test the result of cargo-c
         working-directory: libbz2-rs-sys-cdylib
         run: |
@@ -379,3 +392,6 @@ jobs:
           export LD_LIBRARY_PATH=/tmp/cargo-cbuild-libbzip2-rs/usr/local/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH
           ./bzpipe < Cargo.toml | ./bzpipe -d > out.txt
           cmp -s Cargo.toml out.txt
+          # verify the API surface
+          abidw /tmp/cargo-cbuild-libbzip2-rs/usr/local/lib/x86_64-linux-gnu/libbz2_rs.so > /tmp/liblibz_rs_sys.so.abi
+          abidiff --no-unreferenced-symbols --ignore-soname /tmp/$LIBBZ2_FILENAME.abi /tmp/liblibz_rs_sys.so.abi