This reverts commit fbee943213.
We must not remove any PDB function because we promise API stability
(not only in libgimp, but also in the PDB). Even if this was not used
anywhere in our own scripts/plug-ins, it may be used by third-party
scripts. At best, we can deprecate them so that people are properly warn
that we plan on removing a function. Then we'll remove it for GIMP 4.
Also I believe that various people were not perfectly happy with GEGL's
unsharp-mask operation, compared to the old one. And that was a reason
for keeping the legacy Script-fu version around. See gegl#122 or other
reports which mention such concerns.
At the very least, this should be discussed first with more specialized
developers to determine whether we consider GEGL's replacement operation
to be adequately replacing the historical script by now, so that we can
plan the removal for GIMP 4.
fca4fd1bcc