diff --git a/bin/build-zip.sh b/bin/build-zip.sh
index c8caf5a..05367fb 100755
--- a/bin/build-zip.sh
+++ b/bin/build-zip.sh
@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 # Builds build/m365-login.zip – the folder inside the archive is named after the
 # WordPress.org slug (m365-login), regardless of the repository name.
+# Only needs bash, tar and zip.
 set -euo pipefail
 
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
@@ -11,11 +12,8 @@ STAGE="$BUILD/$SLUG"
 rm -rf "$BUILD"
 mkdir -p "$STAGE"
 
-# rsync honours .distignore-style excludes.
-rsync -a --delete \
-	--exclude-from="$ROOT/.distignore" \
-	--exclude 'build' \
-	"$ROOT/" "$STAGE/"
+# Copy everything except the patterns listed in .distignore.
+tar -C "$ROOT" --exclude-from="$ROOT/.distignore" --exclude='./build' -cf - . | tar -C "$STAGE" -xf -
 
 (
 	cd "$BUILD"
@@ -24,4 +22,4 @@ rsync -a --delete \
 )
 
 echo "Created $BUILD/$SLUG.zip"
-unzip -l "$BUILD/$SLUG.zip" | tail -n +4 | head -n -2 | awk '{print $4}'
+( cd "$STAGE" && find . -type f | sort )