Extract common macOS aarch64 target environment

Author: shepmaster

src/ci/github-actions/jobs.yml

@@ -100,6 +100,12 @@ envs:
     MACOSX_DEPLOYMENT_TARGET: 10.12
     MACOSX_STD_DEPLOYMENT_TARGET: 10.12
 
+  # Aarch64 tooling only needs to support macOS 11.0 as this is the
+  # first OS version to support the hardware.
+  env-macos-aarch64-target: &env-macos-aarch64-target
+    MACOSX_DEPLOYMENT_TARGET: 11.0
+    MACOSX_STD_DEPLOYMENT_TARGET: 11.0
+
 jobs:
   dist-x86_64-linux: &job-dist-x86_64-linux
     name: dist-x86_64-linux
@@ -468,10 +474,7 @@ auto:
         --set rust.jemalloc
         --set rust.lto=thin
         --set rust.codegen-units=1
-      # Aarch64 tooling only needs to support macOS 11.0 and up as nothing else
-      # supports the hardware.
-      MACOSX_DEPLOYMENT_TARGET: 11.0
-      MACOSX_STD_DEPLOYMENT_TARGET: 11.0
+      <<: *env-macos-aarch64-target
       <<: *env-macos-xcode
       DIST_REQUIRE_ALL_TOOLS: 1
       CODEGEN_BACKENDS: llvm,cranelift
@@ -486,10 +489,7 @@ auto:
         --enable-sanitizers
         --enable-profiler
         --set rust.jemalloc
-      # Aarch64 tooling only needs to support macOS 11.0 and up as nothing else
-      # supports the hardware, so only need to test it there.
-      MACOSX_DEPLOYMENT_TARGET: 11.0
-      MACOSX_STD_DEPLOYMENT_TARGET: 11.0
+      <<: *env-macos-aarch64-target
       <<: *env-macos-xcode
     <<: *job-macos