Log Message:
Update autogen to 5.8.3.

Changes since 5.6.4 includes:
* Fixed a small timing hole where the read from the read end of the output
  pipe of the server shell can fail.  (The read is retried.)
* Added a macro for testing mmap failure to accommodate a picky compiler.
* The minor version number is being bumped.  There is a new (albeit tiny)
  feature being added to the syntax.  See the doc on the pseudo-macro.
* Fixed a bug wherein out-of-order definitions could get mistyped causing
  various catastrophic results.
* Definition and license text files were mmap-ed in without checking for
  the size being a multiple of a page.  strlen() would seg fault.
  Horrible, horrible design of mmap!
* disable autoopts/test/getopt.test unless autoopts has been fully installed.
  (It requires getopt.tpl which requires a fully installed environment.)
* several other usability improvements to the tear off library.
* template shell code may now use a shell function "die" that will print
  an error message and shoot down the master autogen process.
* the tear-off/add-in libopts library will now specify that the
  "options.h" header is to be installed.
* realpath(3C) usage in libopts has been cleaned up.  It is now only used
  if PATH_MAX is defined for the platform.  canonicalize_file_name(3C) is
  used where available.