Closes #8033.

  environment variable, to provide an opt-in way to protect against denial of
  service attacks due to hash collisions within the dict and set types.  Patch
  by David Malcolm, based on work by Victor Stinner.

OS X framework builds already created versioned symlinks for all
executables and scripts installed in the framework bin directory,
of the general form ${cmd} - ${cmd}2.7.  The changes here add a
hierarchy of ${cmd} -> ${cmd}2 -> ${cmd}2.7.  Per previous
practice, all of the links are created in the framework bin
directory for both the install and altinstall targets.  This is
consistent with the long-standing recommendation to manage multiple
framework versions by adding and ordering framework bin directories
on $PATH.  Also, per past practice, symlinks to all framework bin
entries are created in $prefix/bin (by default, /usr/local/bin)
for the install target and only versioned links are created for
altinstall, although the use of these links is not recommended
for framework builds and their installation is optional with
the standard OS X installers.

This is needed after the move to Sphinx 1.x and it's the same way 3.x braches
managed it.

upon malformed POST request.

upon malformed POST request.

Initial patch by Torsten Landschoff.

Closes #11689.

Closes #13995.