HEADS-UP: /usr/bin/objdump to be removed

I plan to remove the obsolete GNU binutils 2.17.50 objdump from the
base system in the next few days.

If you currently use objdump from the base system you can give
llvm-objdump a try instead - it is mostly compatible, but has a few
missing options and the output format may be slightly different.
Otherwise, install binutils from ports or packages.

There are a few ports that need adjustment as well, identified in
exp-run PR 212319:

- PR 246229 databases/galera
Fixed by adding a ${LOCALBASE}/bin/objdump:devel/binutils BUILD_DEPENDS.

- PR 241159 devel/powerpc64-gcc (and other *-gcc ports)
The build finishes, but "make package" fails because certain files are missing.

- PR 241157: www/node (and node*)

- No PR yet, graphics/embree

Once this is committed the only remaining obsolete binutils tool will
be /usr/bin/as, on amd64 and i386 only. I expect it will also be
removed for FreeBSD 13.0.