Define 'struct sigvec' properly for the Vision editor.
Define 'struct sigvec' properly for the Vision editor.

The Vision editor (aka, the frontend) has its own version of Vk.h that's different
from the one found in the 'kernel' directory.  Duplicate the changes of commit
https://github.com/vision-dbms/vision/commit/424780edb6b0393e8f8be252807a95b967fe3279 in that file.

VCommitter/vision,vision-dbms/vision,c-kuhlman/vision,c-kuhlman/vision,VisionAerie/vision,vision-dbms/vision,VCommitter/vision,MichaelJCaruso/vision,MichaelJCaruso/vision,MichaelJCaruso/vision,VCommitter/vision,VCommitter/vision,VisionAerie/vision,c-kuhlman/vision,MichaelJCaruso/vision,VisionAerie/vision,MichaelJCaruso/vision,VisionAerie/vision,MichaelJCaruso/vision,vision-dbms/vision,vision-dbms/vision,c-kuhlman/vision,vision-dbms/vision,VCommitter/vision,c-kuhlman/vision,VCommitter/vision,VisionAerie/vision,VisionAerie/vision,VCommitter/vision,vision-dbms/vision,VisionAerie/vision