[RFC] vim-patch:7.4.291

Merging vim-patch:7.4.291

Problem:    Compiler warning for int to pointer of different size when DEBUG
 is defined.
Solution:   use smsg() instead of EMSG3().

https://code.google.com/p/vim/source/detail?r=b5972833add9de714f4651e26fd9ea63ec4a880c