make buildserver-build.sh backwards compatible

Author: dlon

ci/buildserver-build.sh

@@ -196,8 +196,12 @@ function build_ref {
     if [[ "$(uname -s)" == "Darwin" ]]; then
         build_args+=(--universal --notarize)
     fi
+    SUPPORTS_UNIVERSAL_WIN=[[ -d  ]]
     if [[ "$(uname -s)" == "MINGW"* ]]; then
-        build_args+=(--universal)
+        if [[ -d "$BUILD_DIR/windows-installer" ]]; then
+            # build universal build if supported
+            build_args+=(--universal)
+        fi
     fi
 
     artifact_dir=$artifact_dir build "${build_args[@]}" || return 1
@@ -208,6 +212,11 @@ function build_ref {
 
     case "$(uname -s)" in
         MINGW*|MSYS_NT*)
+            if [[ ! -d "$BUILD_DIR/windows-installer" ]]; then
+                echo "Building ARM64 installers"
+                target=aarch64-pc-windows-msvc artifact_dir=$artifact_dir build "${build_args[@]}" || return 1
+            fi
+
             echo "Packaging all PDB files..."
             find ./windows/ \
                 ./target/release/mullvad-daemon.pdb \