Why Linux emulator doesn't understand STB_GNU_UNIQUE binding ?

[Yuri]

I filed this PR: http://www.freebsd.org/cgi/query-pr.cgi?pr=153887

But does anybody have some insight what is not up to date?
I have these lines in my /etc/make.conf:
OVERRIDE_LINUX_BASE_PORT=f10
OVERRIDE_LINUX_NONBASE_PORTS=f10

Is it because linux base port should be updated? Which linux base port 
will have this STB_GNU_UNIQUE?
How can I know which linux base port will correspond to the current Ubuntu?

Yuri