@Paul-Colby i am opening xml file as you mentioned
first time when i pressed save button it will show
<?xml version='1.0'?>
<xml>
<tag1> </tag1> // two spaces from line edit
</xml>

second time when i presses save button it will show

<?xml version='1.0'?>
<xml>
<tag1/> // some data in lineedit
</xml>

third time when i presses save button it will show

<?xml version='1.0'?>
<xml>
<tag1/> // some data in lineedit
</xml>

i am using Qt 4.8.7, i am opening xml file , see the result

Just thought of something: you are trying to cross-compile a linux kernel on OS X. You should rather create a virtual machine using e.g. VirtualBox and do everything directly form Linux. That will save you time.