This, too, was a good call. I put the emulator directory at the start of my search path, just to make sure POSIX wasn't using the system uname to determine its output,
then ran a quick debugging session.
PATH=/emul/ia32-linux/bin:$PATH perl -de 0
Loading DB routines from perl5db.pl version 1.3
Editor support available.
Enter h or `h h' for help, or `man perldebug' for more help.
DB<1> use POSIX
DB<2> x POSIX::uname
3 '#1 SMP Tue Mar 9 09:44:12 UTC 2010'