Comment 2 for bug 1206882

A commit which affected this bug was removed from the repository
git master commit 32941c402015bcdcee2b55cb4f75ace616d8f518
http://git.geda-project.org/pcb/commit/?id=32941c402015bcdcee2b55cb4f75ace616d8f518

commit 32941c402015bcdcee2b55cb4f75ace616d8f518
Author: Markus Hitter <email address hidden>
Commit: Markus Hitter <email address hidden>

    src/res_parse.y: handle resource globals gracefully.

    Likely, res_file is used somewhere to check something. In case a
    resource file was loaded earlier, but the current parsing is from
    a string, res_file is still != NULL, so this check would mislead.

    Solution: Clear res_file and res_filename as soon as the file
              behind it gets closed.

    Also replace a number of zeros with the more appropriate NULL.

    Affects-bug: lp-1206882