add more missing headers
diff --git a/Makefile b/Makefile
index b581a56..08527e4 100644
--- a/Makefile
+++ b/Makefile
@@ -3064,6 +3064,7 @@
     include/grpc++/impl/internal_stub.h \
     include/grpc++/impl/rpc_method.h \
     include/grpc++/impl/rpc_service_method.h \
+    include/grpc++/impl/service_type.h \
     include/grpc++/server.h \
     include/grpc++/server_builder.h \
     include/grpc++/server_context.h \
@@ -3071,6 +3072,7 @@
     include/grpc++/status.h \
     include/grpc++/status_code_enum.h \
     include/grpc++/stream.h \
+    include/grpc++/thread_pool_interface.h \
 
 LIBGRPC++_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC++_SRC))))