By default, error out when we try to compile SVN with ints shorter
than 32 bits.

Via APR, we use ints to index containers for instance.  We assume that
ints are at least 32 bits such that we can handle large numbers of
changed paths in a revision etc.

* subversion/include/private/svn_dep_compat.h
  (): Check for ints to be 32 bits or wider - if that info is
      available and the check has not been disabled.

* notes/knobs
  (1 Introduction): Fix typo
  (SVN_ALLOW_SHORT_INTS): Document the new compile time option.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1570882 13f79535-47bb-0310-9956-ffa450edef68