This reverts commit 996ea03d.

which should only affect Windows unit tests, but should hopefully improve our
chances that Windows unit tests will succeed.

Using concatenation appends the intended filename to the parent directory
name, instead of putting the filename in the parent directory.

It's cool to be able to write 'arg1 << "stuff" << var ...;' for a lambda
accepting a std::ostream reference, but cascading compile errors mean it's no
longer worth trying to make that work -- given actual C++ lambdas.

Also clean up a lingering BOOST_FOREACH() and a boost::bind() while at it.

The recommended template uses hyphens; change to underscores to be valid
Python temp module names.

It seems the problem addressed by aab769e9 wasn't some synergy between
Boost.Phoenix and Boost.Function, but rather the lack of a Phoenix header file
introducing operator<<().

from std::function, since some consumers still use (e.g.)
boost::phoenix::placeholders::arg1 to generate an inline callable.

On GitHub Windows Actions runners, we're getting permissions errors trying to
tell the Python interpreter to run a NamedTempFile script. Try using
NamedExtTempFile to give each such script a .py extension.

do not need 'using' directive, given BOOST_BIND_GLOBAL_PLACEHOLDERS.

The Python child processes used by llprocess_test.cpp and llleap_test.cpp need
the Python llsd module to communicate with the C++ parent process.

Also set LOGFAIL and BUGSPLAT_DB environment variables.

On a low-powered GitHub Mac runner, the system doesn't wake up as soon as it
should, and we get spurious "too late" errors. Try a bigger time increment.

It seems we're no longer implicitly inheriting <array> from some other [set
of] header file[s]. Where we use std::array, bring it in explicitly.

With VS 2022 on Windows GitHub Actions runners, we can't build apr_suite at
all with the upstream .sln / .vcxproj files, so we had to switch to
"experimental" CMake support. However there's no CMakeLists.txt file for
apr-iconv, so the Windows package omits that library.

Let the umbrella <regex.hpp> header make that decision.

This was a longstanding complaint: that Boost shouldn't dump the (somewhat
mysterious) _1, _2 et al. names into the global namespace. Recent Boost has
fixed that, requiring 'using namespace boost::placeholders;' if you want to
use them unqualified.

The package doesn't include that any more.

Update libxml2 to release v2.9.4.7476681.
Update minizip-ng to release v3.0.2.3e9876e.
Update colladadom to release v2.3.d1ef72a.

Update boost to release v1.81-90bb2df.
Update googlemock to release v1.7.0.77bba00.

Not colladadom: a GHA build of something upstream of it produced Mac link
errors seemingly related to zst.

Not xxhash: 3p-xxhash is a private repo, needing the 'public: false' switch in
its build.yaml.

following promotion of DRTVWR-577

Update llphysicsextensions_source to release v1.0.d3192c1.
Update fmodstudio to release v2.02.06.8f8fce1.
Update kdu to release v7.10.4.9e770ae.
Update slvoice to release v4.10.0000.32327.5fc3fe7c.399bd0e.

Update fmodstudio to release v2.02.06.c0dea14.
Update kdu to release v7.10.4.2dc3b89.
Update slvoice to release v4.10.0000.32327.5fc3fe7c.db0dc68.