kde4-runtime, soprano: optional dependency on virtuoso is enforced and prevents building on powerpc

[barracuda156]

kde4-runtime and soprano portfiles claim that virtuoso is not required and will be disabled if not available:

depends_run-append  port:virtuoso

#Virtuoso builds only on 64bit, but it is only a runtime dependency, 
#automatically deactivated if not available (ticket #41773)
depends_skip_archcheck  virtuoso

It does not work this way. What happens in reality is that dependency is enforced, and Macports refuses to build anything:

sergey-fedorovs-power-mac-g5:~ svacchanda$ sudo port -v install soprano
sudo: ignoring time stamp from the future
Password:
Warning: configured user/group macports does not exist, will build as root
--->  Computing dependencies for soprano.........
Error: Cannot install virtuoso for the arch 'ppc' because
Error: its dependency virtuoso-7 only supports the archs 'x86_64 arm64'.

[barracuda156]

In 1e7de87c7779c92770a7adf7fd2bafc21996f90b/macports-ports (master):

virtuoso: add virtuoso-5 to support PowerPC (​https://github.com/macports/macports-ports/pull/19650)

Fixes: #67840
[skip ci]