Unresolved symbol __errno_location

[Patrick Maheral <pmaheral@AAI.ca>]

Hi all,

One of our students is trying to install rtlinux, and keeps getting
a warning message about __errno_location being an unresolved symbol
in rtl_posixio.o.  We have looked through the kernel and rtlinux
source files, but can't find where it is implemented.  The only
thing we found was:

  extern int (*__errno_location)(void);
  #define errno (*(*__errno_location)())

He tried it with 2.2.14 and 2.2.18 kernels and the rtlinux-2.2a
files.  He followed the instructions (including a make mrproper).
What are we missing?

Patrick