- boost-spirit dependency needed to be installed
- Visual Studio wanted boost/filesystem.hpp included in more places
- a deprecated enum was removed from new versions of boost, so we use
its replacement enum now
- vcpkg repository is now pinned to a commit where boost 1.84 libraries
work smoothly, there should be no more surprises
- vcpkg dependencies now cache, so successive CI runs are dramatically
faster
- for win-scons, we need to use 'call' in our batch script to source
vcvarsall.bat
- I updated the includepath and libpath we pass to win-scons to match
reality, but it still can't find any vcpkg libraries. This will need
further sleuthing