vim-patch:7.4.292  #754

Problem:    Searching for "a" does not match accented "a" with new regexp
            engine, does match with old engine. (David Bürgin)
            "ca" does not match "ca" with accented "a" with either engine.
Solution:   Change the old engine, check for following composing character
            also for single-byte patterns.

https://code.google.com/p/vim/source/detail?r=60cdaa05a6ad31cef55eb6b3dc1f57ecac6fcf79