ci: annotate cross-compilation dependency failures

When cross-compile dependency packages cannot be installed, emit
a ::error:: annotation so that the failure reason is visible in
the GitHub Actions summary. Use \r to ensure the annotation is
recognized even inside Docker BuildKit output which prefixes
each line with step and timing information.

Assisted-by: Claude Code (claude-opus-4-6)
Signed-off-by: Adrian Reber <areber@redhat.com>

.github/workflows/ci.yml

@@ -163,6 +163,7 @@ jobs:
     - name: Run Cross Compilation Targets
       run: >
         sudo make -C scripts/ci ${{ matrix.target }}
+        BUILD_OPTIONS="--build-arg CI_CROSS_COMPILE=1"
 
   docker-test:
     needs: [alpine-test]

contrib/dependencies/apt-cross-packages.sh

@@ -6,7 +6,7 @@ if [ ! -x "$APT_INSTALL" ]; then
 	exit 1
 fi
 
-"$APT_INSTALL" \
+if ! "$APT_INSTALL" \
 	crossbuild-essential-"${DEBIAN_ARCH}" \
 	iproute2:"${DEBIAN_ARCH}" \
 	libaio-dev:"${DEBIAN_ARCH}" \
@@ -34,4 +34,13 @@ fi
 	git \
 	protobuf-c-compiler \
 	protobuf-compiler \
-	python3-protobuf
+	python3-protobuf; then
+	if [ -n "$CI_CROSS_COMPILE" ]; then
+		# Use \r to move cursor to the start of the line so that
+		# ::error:: is recognized by GitHub Actions even when
+		# running inside a Docker build where BuildKit prefixes
+		# each line with step and timing information.
+		printf '\r::error::Cross-compile dependency installation failed for %s\n' "${DEBIAN_ARCH}"
+	fi
+	exit 1
+fi

scripts/build/Dockerfile.stable-cross.tmpl

@@ -15,6 +15,9 @@ ENV CROSS_COMPILE=${CROSS_TRIPLET}-				\
 ENV PATH="${PATH}:${CROSS_ROOT}/bin"				\
 	PKG_CONFIG_PATH=/usr/lib/${CROSS_TRIPLET}/pkgconfig
 
+ARG CI_CROSS_COMPILE
+ENV CI_CROSS_COMPILE=${CI_CROSS_COMPILE}
+
 COPY contrib/dependencies/apt-cross-packages.sh /criu/contrib/dependencies/apt-cross-packages.sh
 COPY contrib/apt-install /criu/contrib/apt-install
 WORKDIR /criu

scripts/build/Dockerfile.unstable-cross.tmpl

@@ -15,6 +15,9 @@ ENV CROSS_COMPILE=${CROSS_TRIPLET}-				\
 ENV PATH="${PATH}:${CROSS_ROOT}/bin"				\
 	PKG_CONFIG_PATH=/usr/lib/${CROSS_TRIPLET}/pkgconfig
 
+ARG CI_CROSS_COMPILE
+ENV CI_CROSS_COMPILE=${CI_CROSS_COMPILE}
+
 COPY contrib/dependencies/apt-cross-packages.sh /criu/contrib/dependencies/apt-cross-packages.sh
 COPY contrib/apt-install /criu/contrib/apt-install
 WORKDIR /criu