BUILD: Enhance message if -lXpm is not found.  Dennis van Dok.
BUILD: Enhance message if -lXpm is not found.  Dennis van Dok.

koryonik/swipl-devel,edechter/swipl-devel,jn7163/swipl-devel,edechter/swipl-devel,koryonik/swipl-devel,jn7163/swipl-devel,koryonik/swipl-devel,jn7163/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,edechter/swipl-devel,jn7163/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,edechter/swipl-devel,edechter/swipl-devel,koryonik/swipl-devel,koryonik/swipl-devel,jn7163/swipl-devel,mndrix/swipl-devel