Add a CI job covering the CMake integration

.github/workflows/ci.yml

@@ -200,6 +200,51 @@ jobs:
       - name: Build release
         run: cargo build --workspace --release --verbose
 
+  cmake:
+    name: CMake Integration
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install aarch64 cross toolchain
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y gcc-aarch64-linux-gnu
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: aarch64-unknown-linux-gnu
+
+      # `crates/spacewasm_c_api/README.md` documents consuming the crate through
+      # `add_subdirectory()`, but nothing in CI configures it. The fixture builds
+      # the same two C programs `spacewasm_c_example` already drives through
+      # cargo, so the CMake path gets covered without new test code. Both embed
+      # their module bytes, so unlike the rest of the suite this needs no WABT.
+      - name: Build and run the documented integration
+        run: |
+          cmake -S crates/spacewasm_c_api/tests/cmake -B target/cmake/native \
+            -DCMAKE_BUILD_TYPE=Debug
+          cmake --build target/cmake/native -j"$(nproc)"
+          ./target/cmake/native/ctest
+          ./target/cmake/native/ctest_suite
+
+      # A cross build has to forward the Rust target explicitly. Without
+      # `SPACEWASM_TARGET` cargo still produces a host archive and the link fails
+      # with "file in wrong format", so assert the emitted ELF is AArch64.
+      - name: Cross-compile to aarch64
+        run: |
+          cmake -S crates/spacewasm_c_api/tests/cmake -B target/cmake/aarch64 \
+            -DCMAKE_BUILD_TYPE=Debug \
+            -DCMAKE_SYSTEM_NAME=Linux \
+            -DCMAKE_SYSTEM_PROCESSOR=aarch64 \
+            -DCMAKE_C_COMPILER=aarch64-linux-gnu-gcc \
+            -DSPACEWASM_TARGET=aarch64-unknown-linux-gnu
+          cmake --build target/cmake/aarch64 -j"$(nproc)"
+          readelf -h target/cmake/aarch64/ctest | grep -q AArch64
+
   benchmark:
     name: Benchmark
     runs-on: ubuntu-latest

crates/spacewasm_c_api/tests/cmake/CMakeLists.txt

@@ -0,0 +1,21 @@
+####
+# CMake integration fixture.
+#
+# Consumes `spacewasm_c_api` exactly the way `crates/spacewasm_c_api/README.md`
+# tells an integrator to: `add_subdirectory()` plus a link against `spacewasm`.
+# The programs built here are the same ones `spacewasm_c_example`'s `c_abi.rs`
+# drives through cargo, so this adds coverage of the CMake path without adding
+# test code. Both are self-contained (module bytes are embedded, no file I/O),
+# so unlike the rest of the suite this needs no WABT.
+####
+cmake_minimum_required(VERSION 3.12)
+project(spacewasm_cmake_integration C)
+
+add_subdirectory(../.. spacewasm_c_api)
+
+set(SPACEWASM_C_EXAMPLES ${CMAKE_CURRENT_SOURCE_DIR}/../../../spacewasm_c_example/examples)
+
+foreach(prog ctest ctest_suite)
+  add_executable(${prog} ${SPACEWASM_C_EXAMPLES}/${prog}.c)
+  target_link_libraries(${prog} PRIVATE spacewasm)
+endforeach()