This example of attribute support is from when it was originally added to
EPM in 1989.  Some things have changed since then - e.g., attributes can
now only be added at negative offsets.  Nevertheless, some people might
find these samples to be of some use.  Where the information included
herein differs from that in EPMTECH.INF, the latter should be considered
correct.  Also note that in the original implementation, the attribute
classes were universal variables.  When attribute support was included
in the base set of macros, these were converted to constants for efficiency.
