Add aarch64 host support in alpine rootfs (#14697)

Author: am11

eng/common/cross/build-rootfs.sh

@@ -444,11 +444,18 @@ __RootfsDir="$( cd "$__RootfsDir" && pwd )"
 
 if [[ "$__CodeName" == "alpine" ]]; then
     __ApkToolsVersion=2.12.11
-    __ApkToolsSHA512SUM=53e57b49230da07ef44ee0765b9592580308c407a8d4da7125550957bb72cb59638e04f8892a18b584451c8d841d1c7cb0f0ab680cc323a3015776affaa3be33
     __ApkToolsDir="$(mktemp -d)"
     __ApkKeysDir="$(mktemp -d)"
 
-    wget "https://gitlab.alpinelinux.org/api/v4/projects/5/packages/generic//v$__ApkToolsVersion/x86_64/apk.static" -P "$__ApkToolsDir"
+    arch="$(uname -m)"
+    wget "https://gitlab.alpinelinux.org/api/v4/projects/5/packages/generic/v$__ApkToolsVersion/$arch/apk.static" -P "$__ApkToolsDir"
+    if [[ "$arch" == "x86_64" ]]; then
+      __ApkToolsSHA512SUM="53e57b49230da07ef44ee0765b9592580308c407a8d4da7125550957bb72cb59638e04f8892a18b584451c8d841d1c7cb0f0ab680cc323a3015776affaa3be33"
+    elif [[ "$arch" == "aarch64" ]]; then
+      __ApkToolsSHA512SUM="9e2b37ecb2b56c05dad23d379be84fd494c14bd730b620d0d576bda760588e1f2f59a7fcb2f2080577e0085f23a0ca8eadd993b4e61c2ab29549fdb71969afd0"
+    else
+      echo "WARNING: add missing hash for your host architecture. To find the value, use: `find /tmp -name apk.static -exec sha512sum {} \;`"
+    fi
     echo "$__ApkToolsSHA512SUM $__ApkToolsDir/apk.static" | sha512sum -c
     chmod +x "$__ApkToolsDir/apk.static"