Why gdb on 8.99.12 creates two read/execute segments in debuggable process address space

[cheusov%tut.by@localhost]

Hello. 

NetBSD 8.99.12. Native gdb8 and gdb7 from pkgsrc.

According two '/proc/<PID>/maps' after 'gdb --pid <PID>', the process <PID> have two additional segments 
in address space with R and X flags set. These two segments belong to "/lib/libc.so.12.209" section.

Does any one know why this happens? I don't remember about NetBSD-7 but I didn't see
such things on NetBSD6 and earlier.
Linux also does not create them.