export snip-class because the matrix snips need that to work properly
adjust real-in implementation so that it prints as (real-in ...) instead
of (between/c ...)
meta/pkg-push: improve status and error reporting
raco pkg update: don't claim conflict with package being updated

Merge to v6.1
Fix `Values` in type annotations

Closes PR 14218
fix real-in naming test cases
adjust pack-all script to flush status messages
adjust link-all to avoid conflicts
remote-shell: new package for ssh and VirtualBox utilities

Extracted from "meta/pkg-build" and "distro-build".
add meta/test/unix-installer

Drive a virtual machine to test the Unix installer in various
configurations.
remove obsolte build support

Much of the old build support turned into "distro-build" for
package-based builds, and the "build" directory hasn't been
used for a year or so.
remove old web-page sources

The current web pages are in "new-web" (which should probably
change to just "web", eventually).
remove obsolete distribution specs

Replaced by the package system.
ffi/unsafe/atomic: improve docs
allow mixing exceptions with ffi/unsafe/alloc

Use call-as-atomic that can handle exceptions instead of dynamic-winding
start-atomic and end-atomic. Exceptions can be found in the functions's
result wrapper such as:

    (define-lib find-some-object
                (_fun (name : _string/utf-8)
                      (object : (_ptr o _some-object-pointer))
                      --> (result : _int)
                      --> (begin
                            (when (negative? result)
                              (error 'find-some-object "unknown name"))
                            object))
                #:wrap (allocator free-some-object))

Signed-off-by: Jan Dvořák <mordae@anilinux.org>
mz-gdbinit script gives type when using pso

The mz-gdbinit script (generated by mk-gdbinit.rkt) gives the type when using
pso, even when the default template did not include the type.

It defaults to printing out only the name of the type without additional
information.
meta/pkg-build/main: fix salvage in case of different versions
fix contracts for racket:get-color-prefs-table and
racket:get-white-on-black-color-prefs-table

Apparently these contracts have always been wrong;
5.2.1 had these exports with the wrong contracts and
5.2 didn't have them

closes PR 14664
fix some bugs found by the contract library's random testing

the procedure common-get-file-list was apparently never implemented,
so just remove it
fix contract random generation for -> when the range is 'any'