message: Fix cmake target name repetition error
  Simple check to define the uninstall target only if its not already defined.
  This solves a target name repetition error that occurs when compiling this project along other projects that also use the uninstall target.
diff: @@ -221,8 +221,10 @@ if (MSVC)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /bigobj /wd4251")
  endif(MSVC)
  -# Add the uninstall target
  +# Add the uninstall target if its not defined
  +if(NOT TARGET uninstall)
  include(AddUninstallTarget)
  +endif()
  if (ENABLE_TESTING)
  # Build the test binary
  