Fix build error with hdfs and update dmlc-core (#2107)

* update dmlc-core for hdfs build

* add hdfs support

* default off

* trigger ci

CMakeLists.txt

@@ -26,6 +26,8 @@ dgl_option(USE_CUDA "Build with CUDA" OFF)
 dgl_option(USE_OPENMP "Build with OpenMP" ON)
 dgl_option(BUILD_CPP_TEST "Build cpp unittest executables" OFF)
 dgl_option(LIBCXX_ENABLE_PARALLEL_ALGORITHMS "Enable the parallel algorithms library. This requires the PSTL to be available." OFF)
+dgl_option(USE_S3 "Build with S3 support" OFF)
+dgl_option(USE_HDFS "Build with HDFS support" OFF) # Set env HADOOP_HDFS_HOME if needed
 
 # Set debug compile option for gdb, only happens when -DCMAKE_BUILD_TYPE=DEBUG
 if (NOT MSVC)
@@ -137,10 +139,10 @@ else(USE_CUDA)
 endif(USE_CUDA)
 
 # For serialization
+if (USE_HDFS)
+  option(DMLC_HDFS_SHARED "dgl has to build with dynamic hdfs library" ON)
+endif()
 add_subdirectory("third_party/dmlc-core")
-# dmlc-core options for support S3/HDFS
-add_definitions(-DUSE_S3=OFF)
-add_definitions(-DUSE_HDFS=OFF)
 list(APPEND DGL_LINKER_LIBS dmlc)
 set(GOOGLE_TEST 0) # Turn off dmlc-core test
 

dmlc-core @ 16c6f68c

-Subproject commit 7ce90a342b0bda9b7f88e707a326496324d60efd
+Subproject commit 16c6f68c09af7ed2762cedcd2017307baaf875ed