In revision r446382 about 18 months ago antoine@ added a note to
"Document that the same dependency on gcc as devel/elfutils is recorded".

Alas, devel/elfutils has now moved on from USE_GCC=4.8 to USE_GCC=yes,
and this port builds fine with more current versions as well, so lift
the more restrictive dependency and go for the general one.

On the way unmute an invocation of INSTALL_SCRIPT.