Ensure the new readline interface is used, fixes builds when using the
readline supplied by pkgsrc where the old interface is explicitly disabled.
Update uim to 1.8.4.
based on PR pkg/47468 by YAMASHIRO, Jun.

Overview of changes from 1.8.3 to 1.8.4
=======================================
* Enhancements
  - uim-xim
    * Add Hungarian locale support (by Kővágó Zoltán)
  - uim-tutcode
    * Enhance postfix katakana conversion
      - Take characters while hiragana continues
      - Exclude specified number of characters
      - Shrink last postfix katakana conversion
    * Updated trycode composition table retrieved 2012-11-22


Overview of changes from 1.8.2 to 1.8.3
=======================================
* Fixes
  - uim-toolbar-gtk-systray
  - uim-toolbar-gtk3-systray
    * Avoid SEGV in some environments ([uim-ja 337])
    * Fix typo ([uim-ja 339])

  - uim-tutcode
    * Fix bug: <Shift>left/right key erases current selection text
      on Google Chrome
Updated inputmethod/uim to 1.8.4
Updated inputmethod/uim-elisp to 1.8.4