This patch adjust the x position of preeditarea with both left 
fringe
and left margin, which prevents IME preedit box (such as fcitx) 
from
placing at the wrong position in GUI emacs.

This fixes the bug described in 
https://lists.defectivebydesign.org/archive/html/emacs-devel/2017-02/msg00817.html

I've already assigned the form for contributing to emacs.

regards,
Amos