title: CMake error: Imported targets not available for Boost version 106300
body: <p>I am trying to use uint512_t in a boost library located in:</p>
  
  <blockquote>
    <p>multiprecision/cpp_int.hpp</p>
  </blockquote>
  
  <p>however, when I try to include my boost library through CMake:</p>
  
  <pre><code>cmake_minimum_required(VERSION 3.6)
  project(BoostTest)
  
  set(CMAKE_CXX_STANDARD 11)
  set(BOOSTROOT "/usr/local/Cellar/boost/1.63.0/include")
  
  find_package(Boost REQUIRED)
  if (Boost_FOUND)
      include_directories(${Boost_INCLUDE_DIR})
  endif()
  
  include_directories(${Boost_INCLUDE_DIR})
  
  set(SOURCE_FILES main.cpp)
  add_executable(BoostTest ${SOURCE_FILES})
  </code></pre>
  
  <p>I receive the following error message when compiling:</p>
  
  <pre><code>error: unknown type name 'uint512_t'
  </code></pre>
  
  <p>I don't know what the problem is. I even included: </p>
  
  <blockquote>
    <p>"boost/multiprecision/cpp_int.hpp"</p>
  </blockquote>