Host Environment

• OS: Windows 1909 (OS Build 18363.628)
• Compiler: VS2019 Version 16.3.9

To Reproduce
Steps to reproduce the behavior:
.\vcpkg.exe install boost --triplet x64-uwp

Failure logs
Error: Building package boost-fiber:x64-uwp failed with: BUILD_FAILED
Please ensure you're using the latest portfiles with .\vcpkg update, then
submit an issue at https://github.com/Microsoft/vcpkg/issues including:
Package: boost-fiber:x64-uwp
Vcpkg version: 2020.02.04-nohash-external

Additional context

After checking, it seems following packages were built despite point of failure in the above:

boost-foreach_x64-uwp
boost-format_x64-uwp
boost-function-types_x64-uwp
boost-functional_x64-uwp
boost-function_x64-uwp
boost-fusion_x64-uwp
boost-graph_x64-uwp
boost-hof_x64-uwp
boost-integer_x64-uwp
boost-interprocess_x64-uwp
boost-interval_x64-uwp
boost-intrusive_x64-uwp
boost-io_x64-uwp
boost-iterator_x64-uwp
boost-lambda_x64-uwp
boost-lexical-cast_x64-uwp
boost-logic_x64-uwp
boost-math_x64-uwp
boost-modular-build-helper_x64-uwp
boost-move_x64-uwp
boost-mp11_x64-uwp
boost-mpl_x64-uwp
boost-multi-array_x64-uwp
boost-multi-index_x64-uwp
boost-multiprecision_x64-uwp
boost-numeric-conversion_x64-uwp
boost-odeint_x64-uwp
boost-optional_x64-uwp
boost-parameter_x64-uwp
boost-phoenix_x64-uwp
boost-pool_x64-uwp
boost-predef_x64-uwp
boost-preprocessor_x64-uwp
boost-property-map_x64-uwp
boost-property-tree_x64-uwp
boost-proto_x64-uwp
boost-ptr-container_x64-uwp
boost-random_x64-uwp
boost-range_x64-uwp
boost-rational_x64-uwp
boost-ratio_x64-uwp
boost-regex_x64-uwp
boost-serialization_x64-uwp
boost-signals2_x64-uwp
boost-smart-ptr_x64-uwp
boost-spirit_x64-uwp
boost-static-assert_x64-uwp
boost-system_x64-uwp
boost-thread_x64-uwp
boost-throw-exception_x64-uwp
boost-tokenizer_x64-uwp
boost-tti_x64-uwp
boost-tuple_x64-uwp
boost-type-index_x64-uwp
boost-type-traits_x64-uwp
boost-typeof_x64-uwp
boost-ublas_x64-uwp
boost-units_x64-uwp
boost-unordered_x64-uwp
boost-utility_x64-uwp
boost-uuid_x64-uwp
boost-variant_x64-uwp
boost-vcpkg-helpers_x64-uwp
boost-vmd_x64-uwp
boost-winapi_x64-uwp
boost-xpressive_x64-uwp

Lastly, regression testing should be in place for libs that formerly worked so that new builds are not introduced until all supported platforms are in working order.