Indentation of the output file is broken if there is a indentation in source file

[ptanov]

broken

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<gpx
	xmlns="http://www.topografix.com/GPX/1/1"
	xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3"
	xmlns:wptx1="http://www.garmin.com/xmlschemas/WaypointExtension/v1"
	xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1"
	creator="Dakota 20"
	version="1.1"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd http://www.garmin.com/xmlschemas/GpxExtensions/v3 http://www8.garmin.com/xmlschemas/GpxExtensionsv3.xsd http://www.garmin.com/xmlschemas/WaypointExtension/v1 http://www8.garmin.com/xmlschemas/WaypointExtensionv1.xsd http://www.garmin.com/xmlschemas/TrackPointExtension/v1 http://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
	<metadata>
		<link href="http://www.garmin.com">
			<text>Garmin International</text>
		</link>
		<time>2018-11-15T11:44:24Z</time>
	</metadata>
	<trk>
		<name>Day 10-NOV-18 07:24:58</name>
		<extensions>
			<gpxx:TrackExtension>
				<gpxx:DisplayColor>Cyan</gpxx:DisplayColor>
			</gpxx:TrackExtension>
		</extensions>
		<trkseg>
			<trkpt lat="42.5831057969" lon="23.2922615111">
				<ele>1807.42</ele>
				<time>2018-11-10T05:24:58Z</time>
			</trkpt>
		</trkseg>
	</trk>
</gpx>

results in

<?xml version="1.0" encoding="UTF-8"?><gpx xmlns="http://www.topografix.com/GPX/1/1" xmlns:gpxx="http://www.garmin.com/xmlschemas/GpxExtensions/v3" xmlns:wptx1="http://www.garmin.com/xmlschemas/WaypointExtension/v1" xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" creator="Dakota 20" version="1.1" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd http://www.garmin.com/xmlschemas/GpxExtensions/v3 http://www8.garmin.com/xmlschemas/GpxExtensionsv3.xsd http://www.garmin.com/xmlschemas/WaypointExtension/v1 http://www8.garmin.com/xmlschemas/WaypointExtensionv1.xsd http://www.garmin.com/xmlschemas/TrackPointExtension/v1 http://www.garmin.com/xmlschemas/TrackPointExtensionv1.xsd">
	<metadata>
		<link href="http://www.garmin.com">
			<text>Garmin International</text>
		</link>
		<time>2018-11-15T11:44:24Z</time>
	</metadata>
	<trk>
		<name>Day 10-NOV-18 07:24:58</name>
		<extensions>
			<gpxx:TrackExtension>
				<gpxx:DisplayColor>Cyan</gpxx:DisplayColor>
			</gpxx:TrackExtension>
		</extensions>
		<trkseg>
			<trkpt lon="23.2922615111" lat="42.5831057969">
				<ele>1807.42</ele>
				<time>2018-11-10T05:24:58Z</time>
			<extensions>
					<gpxtpx:TrackPointExtension>
						<gpxtpx:hr>83</gpxtpx:hr>
					</gpxtpx:TrackPointExtension>
				</extensions>
			</trkpt>
		</trkseg>
	</trk>
</gpx>