In this build: https://ci.appveyor.com/project/cpcloud/crossbow/build/1.0.97 the version of boost that is getting picked up is not correct. We're installing boost-cpp=1.67.0 from conda-forge, but BOOST_ROOT is somehow getting picked up as C:\Libraries\boost_1_63_0.
We're setting ARROW_BUILD_TOOLCHAIN and PARQUET_CPP_BUILD_TOOLCHAIN correctly.
Krisztian Szucs [~wesmckinn] Do you know if BOOST_ROOT overrides setting those other envars?
I don't think this is the cause of the failing build here, since this build (https://ci.appveyor.com/project/kszucs/crossbow/build/1.0.391) passes with that envar set to boost 1.63, but it's still incorrect so we should fix it.