scribble: fix PDF rendering of references to unnumbered sections

Instead of "section" or "part" without a folowing number,
a reference to an unnumbered section renders as the section
name in quotes and then "on page <n>" (to help clarify that
the quoted part is a section name).

More generally, enable LaTeX macros for `secref' to work with the
LaTeX-level label (to expand to a page number, for example) in
the case of document-local references.

Closes PR 13935
scribble Latex: make numbered subsections work in an unnumbered section
scribble/manual: add space before "packages:" to look better in text output
judgment-form: fix for nested metafunctions

These were being handled in the wrong order,
which sometimes makes search more difficult.
fix examples path in run-tests.rkt
configure: pass `--enable-portable-binary' to libffi configure

The `--enable-portable-binary' flag disables optimizations specific
to the build machine's processor that may ne unportable to other
machines.

This also fixes a problem where a VirtualBox runs on an x86_64 machine
with AVX support, and so `congure' enables AVX operations, but AVX
doesn't work within a virtual machine.
remove debugging printout
fix and fill in responsibility props
add "distributed-places" package

Joins the "-lib" and "-doc" packages.
rename "typed-racket-tests" package to "typed-racket-test"
Update RacketCon 2012 link
Restored behavior of set/c for flat contracts; #:kind defaults to 'immutable.
Updated tests for set/c.

Restored test for first-order check of elements when given a flat contract.
Added tests for #:kind 'mutable.