The Free On-line Dictionary of Computing (30 December 2018):

x-scm

    An accessory for the scm Scheme interpreter,
   by Larry Campbell, that provides an environment for building
   Motif and OpenLook application programs.  There is some
   support as well for raw Xlib applications, but not enough
   yet to be useful.

   Posted to alt.sources.

   (1992-08-10)