Because the gworkspace ebuild is so out of date compared to the latest release of gworkspace, the gworkspace-0.5.3.ebuild doesn't seem to exist on the gworkspace webpage any longer (http://www.gnustep.it/enrico/gworkspace)
here's the error from emerge:
>>> Deleting invalid distfile. (Improper 404 redirect from server.)
!!! Couldn't download gworkspace-0.5.3.tar.gz. Aborting.
Steps to Reproduce:
emerge failed with the above error.
download gworkspace-0.5.3.tar.gz into portage/distfiles for compiling.
all of the GNUStep ebuilds are embarassingly out of date.
newer package available