--- rabit/CMakeLists.txt.orig	2019-12-14 20:43:47 UTC
+++ rabit/CMakeLists.txt
@@ -13,7 +13,7 @@ set(DMLC_ROOT ${CMAKE_CURRENT_LIST_DIR}/../dmlc-core)
 
 # moved from xgboost build
 if(R_LIB OR MINGW OR WIN32)
-  add_library(rabit src/engine_empty.cc src/c_api.cc)
+  add_library(rabit SHARED src/engine_empty.cc src/c_api.cc)
   set(rabit_libs rabit)
   set_target_properties(rabit
           PROPERTIES CXX_STANDARD 11
@@ -21,10 +21,10 @@ if(R_LIB OR MINGW OR WIN32)
           POSITION_INDEPENDENT_CODE ON)
 else()
   find_package(Threads REQUIRED)
-  add_library(rabit_empty src/engine_empty.cc src/c_api.cc)
-  add_library(rabit_base src/allreduce_base.cc src/engine_base.cc src/c_api.cc)
+  add_library(rabit_empty SHARED src/engine_empty.cc src/c_api.cc)
+  add_library(rabit_base SHARED src/allreduce_base.cc src/engine_base.cc src/c_api.cc)
 
-  add_library(rabit src/allreduce_base.cc src/allreduce_robust.cc src/engine.cc src/c_api.cc)
+  add_library(rabit SHARED src/allreduce_base.cc src/allreduce_robust.cc src/engine.cc src/c_api.cc)
   add_library(rabit_mock_static src/allreduce_base.cc src/allreduce_robust.cc src/engine_mock.cc src/c_api.cc)
   add_library(rabit_mock SHARED src/allreduce_base.cc src/allreduce_robust.cc src/engine_mock.cc src/c_api.cc)
   target_link_libraries(rabit Threads::Threads)
@@ -43,7 +43,7 @@ if(RABIT_BUILD_MPI)
   if (NOT MPI_CXX_FOUND)
     message(FATAL_ERROR "CXX Interface for MPI is required for building MPI backend.")
   endif (NOT MPI_CXX_FOUND)
-  add_library(rabit_mpi src/engine_mpi.cc ${MPI_INCLUDE_PATH})
+  add_library(rabit_mpi SHARED src/engine_mpi.cc ${MPI_INCLUDE_PATH})
   target_link_libraries(rabit_mpi ${MPI_CXX_LIBRARIES})
   list(APPEND rabit_libs rabit_mpi)
 endif()