Merge #161: cmake: Avoid including CTest if not top level project

a7f0669 cmake: Avoid including CTest if not top level project (Ryan Ofsky)

Pull request description:

  Avoid including CTest in if this is not a top-level cmake project because as reported #145 (comment) this adds a `BUILD_TESTING` option could be confused for Bitcoin core's `BUILD_TESTS` option.

Top commit has no ACKs.

Tree-SHA512: c28d8c9a43f23d7d1e91c914c777695fe422105a347133194b547e28217dd94be5418a1384b8c83b41fc173ee1b49fcd4656114f75d169d0cabc78ea2615d681

Author: ryanofsky

CMakeLists.txt

@@ -28,13 +28,13 @@ set(MPGEN_EXECUTABLE "" CACHE FILEPATH "If specified, should be full path to an
 
 include("cmake/compat_config.cmake")
 include("cmake/pthread_checks.cmake")
-include(CTest)
 include(GNUInstallDirs)
 
 # Set convenience variables for subdirectories.
 set(MP_INCLUDE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/include")
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(MP_STANDALONE TRUE)
+  include(CTest)
 else()
   # Set MP_INCLUDE_DIR for parent directories too, so target_capnp_sources calls
   # in parent directories can use it and not need to specify include directories