Prefer $(...) over backticks, drop the space before ";" in
conditionals, and normalize sentence-ending punctuation and line
wrapping in comments.

Use printf %s for metalog entries built from path variables so
backslash sequences in paths are printed verbatim.

Collapse the remaining split for loops onto one line to match the
style already used elsewhere in defaults.sh.

Replace sort | uniq with sort -u in setup_nanobsd() and cust_pkgng().

No functional change.