improve debug-release build script

xwords4/android/scripts/build-debug.sh

@@ -4,14 +4,35 @@ DIR=/tmp/build_$$_dir
 mkdir -p $DIR
 pushd $DIR
 
+usage() {
+    [ $# -ge 1 ] && echo "Error: $1"
+    echo "builds debug variant from the current tip of github"
+	echo "(last modified Jan 2024)"
+    exit 1
+}
+
+while [ $# -ge 1 ]; do
+    case $1 in
+		--help)
+			usage
+			;;
+		*)
+			usage "unexpected command $1"
+			;;
+	esac
+	shift
+done
+
 git clone https://github.com/eehouse/xwords.git
 cd xwords/xwords4/android
 ./gradlew asXw4dDeb
 
+APK="$(find . -name '*.apk')"
 if [ -n "${XW4D_UPLOAD}" ]; then
-	scp $(find . -name '*.apk') ${XW4D_UPLOAD}
+	scp "$APK" ${XW4D_UPLOAD}
+	echo "uploaded $APK"
 else
-	echo "not uploading: XW4D_UPLOAD not set" >&2
+	echo "not uploading $APK: XW4D_UPLOAD not set" >&2
 fi
 
 popd