It's very easy to miss some dependencies in ports. With recent additions, unless you really don't have any space available, I heartily recommend reproducing the build in a chroot.
That's about as difficult as using proot -B /build (or some other location), making darn sure that partition is dev,wxallowed, and then copying the requisite parts of the ports tree. (if you do frequent port development, you might consider locating your ports tree INSIDE the chroot, actually). Also, you really really want to pay close attention to configure output. Especially about parts that DO exist in the ports tree (pkglocatedb is your friend, so is sqlports). And finally, setting things up for PORTS_PRIVSEP will help you avoid some other issues. One nice thing with this is that the build is done as _pbuild which has *no network access whatsover*. All of this should help avoid quite a few 'hidden dependencies' or 'incomplete port' issues that we tend to figure out when running actual full builds or reviewing ports...
