Workaround the following problem on aarch64 by setting LLD_UNSAFE=yes:

cc: error: invalid linker name in argument '-fuse-ld=bfd'

Neither emaste nor I can figure out exactly where the offending stanza is
coming in. It will take someone with more knowledge of gmake debug flags,
and possibly the src build infrastructure, to figure it out.

While here, pet portlint.

Approved by: portmgr (tier-2 blanket)