gitlab: Enable CI for wasm build

Add GitLab CI job that builds QEMU using emscripten. The build runs in the
container defined in tests/docker/dockerfiles/emsdk-wasm32-cross.docker.

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
Link: https://lore.kernel.org/r/ade0deb2dc65618a91755590f6729485b4001b94.1745820062.git.ktokunaga.mail@gmail.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

.gitlab-ci.d/buildtest-template.yml

@@ -115,3 +115,30 @@
     - du -chs ${CI_PROJECT_DIR}/*-cache
   variables:
     QEMU_JOB_FUNCTIONAL: 1
+
+.wasm_build_job_template:
+  extends: .base_job_template
+  stage: build
+  image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:$QEMU_CI_CONTAINER_TAG
+  before_script:
+    - source scripts/ci/gitlab-ci-section
+    - section_start setup "Pre-script setup"
+    - JOBS=$(expr $(nproc) + 1)
+    - section_end setup
+  script:
+    - du -sh .git
+    - mkdir build
+    - cd build
+    - section_start configure "Running configure"
+    - emconfigure ../configure --disable-docs
+          ${TARGETS:+--target-list="$TARGETS"}
+          $CONFIGURE_ARGS ||
+      { cat config.log meson-logs/meson-log.txt && exit 1; }
+    - if test -n "$LD_JOBS";
+      then
+        pyvenv/bin/meson configure . -Dbackend_max_links="$LD_JOBS" ;
+      fi || exit 1;
+    - section_end configure
+    - section_start build "Building QEMU"
+    - emmake make -j"$JOBS"
+    - section_end build

.gitlab-ci.d/buildtest.yml

@@ -792,3 +792,12 @@ coverity:
       when: never
     # Always manual on forks even if $QEMU_CI == "2"
     - when: manual
+
+build-wasm:
+  extends: .wasm_build_job_template
+  timeout: 2h
+  needs:
+    job: wasm-emsdk-cross-container
+  variables:
+    IMAGE: emsdk-wasm32-cross
+    CONFIGURE_ARGS: --static --disable-tools --enable-debug --enable-tcg-interpreter

.gitlab-ci.d/container-cross.yml

@@ -91,3 +91,8 @@ win64-fedora-cross-container:
   extends: .container_job_template
   variables:
     NAME: fedora-win64-cross
+
+wasm-emsdk-cross-container:
+  extends: .container_job_template
+  variables:
+    NAME: emsdk-wasm32-cross