Update Ini File Class.cpp

Fix Project64.cfg from getting corrupted when moving the window around.
https://github.com/project64/project64/issues/225

Source/Common/Ini File Class.cpp

@@ -738,6 +738,7 @@ void CIniFileBase::SaveNumber ( LPCTSTR lpSectionName, LPCTSTR lpKeyName, ULONG
 
 void CIniFileBase::FlushChanges (void)
 {
+	CGuard Guard(m_CS);
 	SaveCurrentSection();
 }