[Lazarus] {$warn 5023 off: No warning about unused units}

[Werner Pamler]

Since some time, the TurtoiseSVN overlay icons of some of the packages 
which I loaded from svn have become practically useless. It is always 
the autogenerated package unit which is marked by a red overlay icon as 
being out of date. When I open the unit I see that the line

{$warn 5023 off : no warning about unused units}

has been added to the unit header. Deleting the unit, updating it from 
the svn repository fixes it for the moment, the "no warning about unused 
units" line is gone, and the overlay icon is green. But when I open the 
package and recompile it the line comes back, and the icon turns read again.

There must be something in my Lazarus settings which inserts this line.

Could anybody give me a hint where to look?

I am having this issue with Laz trunk / fpc 3.0 on Win7.