title: CMake error "include could not find load file: FetchContent"
body: <p>I am getting the following error while executing the <code>cmake</code> command on Ubuntu. CMake version - 3.10.2.</p>
  <pre><code> mapp@ubuntu:~/Desktop/LocatePro$ cmake .
   -- Enable testing: ON
   CMake Error at CMakeLists.txt:40 (include):
    include could not find load file:
  
     FetchContent
  
  
  CMake Error at CMakeLists.txt:42 (FetchContent_Declare):
     Unknown CMake command &quot;FetchContent_Declare&quot;.
  
   -- Configuring incomplete, errors occurred!
      See also &quot;/home/mapp/Desktop/LocatePro/CMakeFiles/CMakeOutput.log&quot;.
   mapp@ubuntu:~/Desktop/LocatePro$ 
  </code></pre>
  <p>Following is the <code>CMakeLists.txt</code> content from line no. 31:</p>
  <pre><code># we will use the network to fetch Google Test sources
  # make it possible to disable unit tests when not on network
  option(ENABLE_UNIT_TESTS &quot;Enable unit tests&quot; ON)
  message(STATUS &quot;Enable testing: ${ENABLE_UNIT_TESTS}&quot;)
  
  if(ENABLE_UNIT_TESTS)
  # the following code to fetch googletest
  # is inspired by and adapted after:
  #   - https://cmake.org/cmake/help/v3.11/module/FetchContent.html
  include(FetchContent)
  
  FetchContent_Declare(
  googletest
  GIT_REPOSITORY https://github.com/google/googletest.git
  GIT_TAG        release-1.8.0
  )
  
  FetchContent_GetProperties(googletest)
  
  if(NOT googletest_POPULATED)
      FetchContent_Populate(googletest)
  
      # Prevent GoogleTest from overriding our compiler/linker options
      # when building with Visual Studio
      set(gtest_force_shared_crt ON CACHE BOOL &quot;&quot; FORCE)
      # Prevent GoogleTest from using PThreads
      set(gtest_disable_pthreads ON CACHE BOOL &quot;&quot; FORCE)
  
      # adds the targers: gtest, gtest_main, gmock, gmock_main
      add_subdirectory(
        ${googletest_SOURCE_DIR}
        ${googletest_BINARY_DIR}
        )
  
      # Silence std::tr1 warning on MSVC
      if(MSVC)
        foreach(_tgt gtest gtest_main gmock gmock_main)
          target_compile_definitions(${_tgt}
            PRIVATE
              &quot;_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING&quot;
            )
        endforeach()
      endif()
    endif()
  
   add_executable(LocatPro_Test &quot;&quot;)
  
   target_sources(LocatPro_Test
      PRIVATE
      LocatProTest/LocatProTest.cpp
     )
  
    target_link_libraries(LocatPro_Test
       PRIVATE
       gtest_main
     )
  
    enable_testing()
  
    add_test(
       NAME google_test
       COMMAND $&lt;TARGET_FILE:LocatPro_Test&gt;
       )
  endif()
  </code></pre>
  <p>I am new to and today only I started working on CMake.
  Please let me know if I am doing anything wrong and/or missing anything in CMake.</p>
  <p><code>include(FetchContent)</code> is supporting in CMAke version - 3.10.2 on Ubuntu.</p>