CMake outputs an error when using Boost 1.76 on Mac OS X Catalina

[KungFuFurby]

Using boost 1.76, installed via MacPorts, gave me this error on CMake during compilation:

CMake Error at /opt/local/lib/cmake/Boost-1.76.0/BoostConfig.cmake:141 (find_package):
  Found package configuration file:

    /opt/local/lib/cmake/boost_filesystem-1.76.0/boost_filesystem-config.cmake

  but it set boost_filesystem_FOUND to FALSE so package "boost_filesystem" is
  considered to be NOT FOUND.  Reason given by package:

  No suitable build variant has been found.

  The following variants have been tried and rejected:

  * libboost_filesystem.dylib (shared, Boost_USE_STATIC_LIBS=YES)

Call Stack (most recent call first):
  /opt/local/lib/cmake/Boost-1.76.0/BoostConfig.cmake:258 (boost_find_component)
  /opt/local/share/cmake-3.22/Modules/FindBoost.cmake:594 (find_package)
  src/CMakeLists.txt:16 (find_package)

My instincts say that this is probably a problem with Boost 1.70 and up.

I am using an Intel Mac running Mac OS X 10.15.7. The other dependencies have already been installed.