- Adds and integrates pkgconf_host and pkgconf; fixes Irssi and other
      packages that depend on pkg-config(1) and makes their build variables
      significantly less hacky (apk_tools, irssi, nano, ncurses, ncursestw
      ncursesw, and pacman.) pkgconf_host installs a ${TARGET}-pkg-config
      wrapper script that passes --define-variable=prefix=${PREFIX_NATIVE}
      when cross-compiling.
    - Adds -i flag to insert a link to pkg.build for a new build script
      and automatically rename build scripts with higher consecutive build
      levels.
    - Consistently quote [(1) operands correctly wherever necessary.
    - Reorganise build level 3 script levels:
      1) 300-319: library dependencies, ordered by dependencies and alphabetically,
      2) 320-389: leaf packages, ordered alphabetically.