FIXED: library(prolog_xref): several bugs in handling :- reexport
FIXED: library(prolog_xref): several bugs in handling :- reexport

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