gitlab-ci: add Rust-enabled CI job

Add a job using --enable-rust, to ensure that the toolchain is installed
correctly by the Dockerfile and that QEMU builds with Rust enabled on
at least one platform.

Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

.gitlab-ci.d/buildtest.yml

@@ -120,6 +120,19 @@ build-system-fedora:
       xtensa-softmmu m68k-softmmu riscv32-softmmu ppc-softmmu sparc64-softmmu
     MAKE_CHECK_ARGS: check-build
 
+build-system-fedora-rust-nightly:
+  extends:
+    - .native_build_job_template
+    - .native_build_artifact_template
+  needs:
+    job: amd64-fedora-rust-nightly-container
+  variables:
+    IMAGE: fedora-rust-nightly
+    CONFIGURE_ARGS: --disable-docs --enable-rust
+    TARGETS: aarch64-softmmu
+    MAKE_CHECK_ARGS: check-build
+  allow_failure: true
+
 check-system-fedora:
   extends: .native_test_job_template
   needs:

.gitlab-ci.d/containers.yml

@@ -27,3 +27,9 @@ python-container:
   extends: .container_job_template
   variables:
     NAME: python
+
+amd64-fedora-rust-nightly-container:
+  extends: .container_job_template
+  variables:
+    NAME: fedora-rust-nightly
+  allow_failure: true