redex: add typed generators to the benchmark

- change delim-cont to generate a store as well
- add version of rvm that works with #:satisfying
- add version of list-machine that works with #:satisfying
- new rewrites for the above
- infrastructure to wire all of this together
fix delim-cont tests
fix redex benchmark dependencies
Fix type for read-bitmap

Closes PR 14729
configure: add `--enable-natipkg` and 64-bit Linux native libraries

The `--enable-natipkg` configuration option adds "-natipkg" to the
platform library subpath. The suffix is intended to trigger the
installation of packages that supply native libraries for supported
platforms (where 64-bit Linux is the supported platform, for now, for
main-distribution packages), instead of relying on libraries installed
via the OS's package manager.

The intended client for "-natipkg" is the package-build service, where
installing packages via the OS package manager would require network
access and either trust or constrained installations. The build
machine is intentionally disconnected from the network and can only
access Racket packages, so repackaging native libraries as Racket
packages makes those libraries accessible.

A disadvantage of this approach to installing native libraries is that
it creates work for implementers of packages that access native
libraries. Those implementers will have to supply packages for 64-bit
Linux versions of native libraries to the degree needed to build and
(eventually) test the package. An advantage of the approach is that it
requires no changes to the package system; it will be cheap to replace
this approach if we find a better way to deal with native libraries
and/or OS packages in the package-build service.
distro-build: "detail" label rendering on download page
Use bytes consistently in regexmatch.

Inconsistency found by Tobias Pape, see GH issue #792.
redex: fix distribution cache in search
add missing file from previous push
Alpha version number for the v6.1.1 release
add missing "x86_64-linux-natipkg" dependency

Merge to v6.1.1

(cherry picked from commit 079ea21dabce1ffda6e3e5f99da5efd881b4e61b)
fix allocation bug in `equal?` on deeply nested values

Based on the core file, this bug seems likely responsible for the
`raco setup` crash on DrDr for push 29346.

Merge to v6.1.1

(cherry picked from commit 7e984c600957ac5d9ccf366b3f9377e206d56960)
macro expander: fix an internal hash-table traversal bug

This bug could result in weird "cannot re-define a constant: lifted.0.2"
errors, or probably even worse collsisions of definitions, but I think
only in a namespace created from `module->namespace`.

So far, I haven't been able to create a reasonably small test,
because so many things have to line up in just the right way.

Merge to v6.1.1

(cherry picked from commit d4ad0a20e40ec7f7ffa7907470fc7dda76e59c15)
add a description of the bugs in the benchmark to the documentation

please include in the release

(cherry picked from commit ef76c273ea31e866ba4e1758e4747323e7ac9f67)
ffi/unsafe: fix `make-sized-byte-string` on a #f argument

In particular, a #f argument can make sense if the length is 0.
Technically, a byte string's byte array is supposed to be nul-terminated,
but many uses of byte strings get away without that terminator. I've
adjust the documentation to note that `bytes-copy` will work with a
non-terminated byte string.

Merge to v6.1.1

(cherry picked from commit 1cc86d3cea4763d70e4a155e286305215519a23d)
Get rid of some unused code.

Looks like some aborted attempt at abstraction, which is no longer used.

(cherry picked from commit 2e6b82ab8ec0cc63837759873e412831de5a1826)
Get rid of `special-dots-printing?'.

Asumu said that he doesn't know of any other clients of this parameter
besides my class code.

(cherry picked from commit 0eed0f6e0e493b190abc912981bab59644a3a760)
Add `type-output-sexpr-tweaker'.

Sounds like a bad name, but I don't have anything better.  It's not some
"current-...-print" thing since it works on the sexpr that is intended
to be pretty-printed.  So I went with the above.

(cherry picked from commit 3c98d086904409b9c49d710134415d718d6ca65e)
Random improvement.

The thing that caught my eye is the missing `#:cache-keys?' which should
really be there.  But not too important.

(cherry picked from commit eaa6f85054c5c404507e5c9cbab0d3e93f468370)
Fix printing of * in -> types

(cherry picked from commit 38af459049819ecac24de6b349440e6c589703f9)