For some reason, we used "vc_x64_lib" as the output directory for the
libraries, but "vc_mswu_x64" as the output directory for the samples.
Place the arch suffix, i.e. "_x64" part, always after the compiler
prefix (possibly including version), for consistency with both the
library output directories and with MSBuild project files, as
build/msw/wx_setup.props uses $(wxCompilerPrefix)$(wxArchSuffix)_...
as wxIntRootDir value.
