standalone-installer-unix: Use new macOS on aarch64 builds

For merge to master after the first release with aarch64 builds
available.¹

¹ <#357>

CHANGES.md

@@ -16,8 +16,13 @@ development source code and as such may not be routinely kept up to date.
 ## Improvements
 
 * We now produce standalone installation archives for macOS running on aarch64
-  hardware (aka arm64, Apple Silicon, M1/M2).
-  ([#357](https://github.com/nextstrain/cli/pull/357))
+  hardware (aka arm64, Apple Silicon, M1/M2).  The standalone installer will
+  use these archives starting with this release.  Rosetta 2 is still required
+  to be enabled at install time, as it's still needed by Nextstrain's Conda and
+  Docker runtimes.  This requirement may be relaxed in the future since not all
+  Nextstrain CLI commands use a runtime.
+  ([#357](https://github.com/nextstrain/cli/pull/357),
+  [#358](https://github.com/nextstrain/cli/pull/358))
 
 
 # 8.0.1 (29 January 2024)

bin/standalone-installer-unix

@@ -115,9 +115,28 @@ target-triple() {
             ;;
 
         Darwin)
-            [[ "$machine" == x86_64 || "$machine" == arm64 ]] || die "unsupported architecture: $machine"
+            # XXX TODO: Move this check for Rosetta closer to the places that
+            # require it.  With standalone builds for aarch64 now, Rosetta 2 is
+            # technically not needed for Nextstrain CLI itself anymore.  The
+            # Conda runtime still requires it and I believe the Docker runtime
+            # does too.  But someone could use non-runtime CLI commands (e.g.
+            # `nextstrain remote`) without Rosetta.
+            #  -trs, 1 Feb 2024
             [[ "$machine" != arm64 ]] || pgrep -qU _oahd 2>/dev/null || die "Rosetta 2 not enabled.  Please run:"$'\n\n'"    softwareupdate --install-rosetta"$'\n\n'"and then retry this installation of Nextstrain CLI."
-            machine=x86_64
+
+            # XXX TODO: Consider checking VERSION here so we only use aarch64
+            # builds _after_ the first release in which they're supported?  As
+            # it stands now, if you want to install an older version and are on
+            # aarch64 hardware it will fail as the builds don't exist.  The
+            # workaround is to set TARGET=x86_64-apple-darwin when running the
+            # installer.  This probably doesn't affect many people (mostly
+            # devs?) so I'm opting to skip it for now.
+            #  -trs, 1 Feb 2024
+            case "$machine" in
+                x86_64) ;;
+                arm64) machine=aarch64;;
+                *) die "unsupported architecture: $machine";;
+            esac
             vendor=apple
             os=darwin
             ;;