Subject:   -39- How can I generate IRIX 4.0.x-compatible executables
                under IRIX 5.x?
Date: 10 Dec 1993 00:00:01 EST

  Strictly speaking, you can't. Many things changed in IRIX 5.x. You
  can, however generate executables in COFF (IRIX 4.0.x) format instead
  of ELF (IRIX 5.x) format, and these will often work on IRIX 4.0.x if
  they don't use complex things like multiprocessing. The manual and
  release notes describe how, and here's a summary:

  1) Make sure you've installed all of the appropriate irix4
     compatibility subsystems. These include irix4_eoe, irix4_dev,
     irix4_c and others for Motif, Inventor, etc.

  2) setenv SGI_IRIX4 1

  3) If your source uses explicit paths to headers, libraries, etc.,
     change them to point to the irix4 versions.

  4) Use cc or make or whatever as you normally would.