o Minor bugfixes:
    - Change $(VAR:MOD) to ${VAR:MOD} -- make(1) on
      NetBSD substitutes '$(:x)' to 'x' rather than the empty string.  This
      bites us in doc/ when configured with `--disable-asciidoc'.  Curly
      braces should work in all implementations of make(1) but this patch
      changes only the places where we use the VAR:MOD expansion.