PORT: Do not trust return from Windows GetEnvironmentVariable() API.
PORT: Do not trust return from Windows GetEnvironmentVariable() API.

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