vim-patch: Mark patches as NA.
Merge pull request #1676 from fwalch/na-patches

vim-patch: Mark patches as NA.
Little by little add 'const' were possible: mbyte.c
Merge pull request #1677 from philix/dpelle-constify

add 'const' where possible: mbyte.c (rebase of #268)
Fix warning: ops.c: read_viminfo_register():  Dereference of null pointer: RI.

Problem    : Array access (via field 'y_array') results in a null pointer
             dereference @ 4487.
Diagnostic : Real issue.
Rationale  : If the array was previously freed and the size of the array
             (y_current->y_size) was not updated to zero, the loop @4486
             could be entered and a NULL pointer would be dereferenced.
Resolution : Use free_yank_all() to take care of the NULL check and
             to free the current yank register.
Merge pull request #1679 from oni-link/fix.clang.warning

Fix for clang analyzer warning in ops.c
Remove VMS remnants
Remove dec-mcs remnants

It was (apparently) the default character encoding file used for line
printing on VMS, which is unsupported.
Remove Amiga remnants

Notes regarding the removal of specific items:

  - Aztec C: only on the Amiga.
  - mch_check_win(): doesn't exist anymore.
  - Comment in ex_cmds.c: It seems the context for this comment was
    removed, but the comment was inadvertantly left alone.