message: Add documentation warning about memory usage during builds
diff: @@ -33,6 +33,10 @@ Alternatively, on a non-SGX machine, you can build a `virtual` instance of CCF:
  CCF defaults to building in the `RelWithDebInfo <https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html>`_ configuration.
  +.. warning::
  +
  + A machine with at least 32Gb of memory is recommended to build CCF with the default compiler.
  +
  Build Switches
  --------------
  