ci: Add workflow step for static build with libbfd

It's trivial to add an additional step to the build workflows for doing
a static build with libbfd. We need libiberty-dev for that.

Static build with LLVM, however, requires compiling and installing the
static libraries first. This is left aside for now.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>

.github/workflows/build.yaml

@@ -26,7 +26,7 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y \
-              libbfd-dev libcap-dev libelf-dev python3-docutils
+              libbfd-dev libcap-dev libelf-dev libiberty-dev python3-docutils
           # clang/LLVM are already installed, but we're missing some aliases.
           CLANG_VERSION="$(echo '__clang_major__' | clang -E - | tail -n 1)"
           sudo update-alternatives \
@@ -67,6 +67,18 @@ jobs:
               tee /dev/stderr | \
               jq --exit-status ".features | .libbfd and (.llvm | not)"
 
+      - name: Build bpftool, with libbfd, static build
+        run: |
+          make -C src clean
+          EXTRA_CFLAGS=--static make -j -C src V=1
+          ./src/bpftool 2>&1 | grep -q Usage
+          ./src/bpftool -p version | \
+              tee /dev/stderr | \
+              jq --exit-status ".features | .libbfd and (.llvm | not)"
+          ldd ./src/bpftool 2>&1 | \
+              tee /dev/stderr | \
+              grep -q 'not a dynamic executable'
+
       - name: Build bpftool's documentation
         run: |
           make -j -C docs