CI: add packaging test for the binary Arm compilers

Add a trivial job that verifies the binary Arm compiler packages all
fetch and package correctly for both x86-64 and arm64.

Change-Id: I1e29cc175d66d418630505dcac1a87cdf5c0024a
Signed-off-by: Ross Burton <ross.burton@arm.com>
Reviewed-by: Denys Dmytriyenko <denis@denix.org>
Signed-off-by: Jon Mason <jon.mason@arm.com>

.gitlab-ci.yml

@@ -101,6 +101,9 @@ check-layers:
   - kas shell --update --force-checkout ci/base.yml:ci/meta-arm-autonomy.yml:ci/meta-python.yml --command \
     "$CI_PROJECT_DIR/ci/check-layers.py $CI_PROJECT_DIR/ci/check-layers.yml $CI_PROJECT_DIR $KAS_WORK_DIR"
 
+toolchains:
+  extends: .build
+
 corstone500:
   extends: .build
 

ci/toolchains.yml

@@ -0,0 +1,20 @@
+header:
+  version: 9
+  includes:
+    - base.yml
+
+# Target is arm64 and SDK is x86-64 to ensure that we exercise both
+# architectures
+
+machine: qemuarm64
+local_conf_header:
+  toolchains: |
+    SDKMACHINE = "x86_64"
+
+# No target armcompiler as currently there is no arm64 build
+target:
+  - nativesdk-armcompiler
+  - gcc-aarch64-none-elf
+  - nativesdk-gcc-aarch64-none-elf
+  - gcc-arm-none-eabi
+  - nativesdk-gcc-arm-none-eabi