FIXED: save_backtrace() if threads are not yet initialized.  Keri Harris.
FIXED: save_backtrace() if threads are not yet initialized.  Keri Harris.

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