port_platform should be included since that's where NONEXPERIMENTAL is specified

include/grpcpp/impl/codegen/async_generic_service.h

@@ -19,6 +19,8 @@
 #ifndef GRPCPP_IMPL_CODEGEN_ASYNC_GENERIC_SERVICE_H
 #define GRPCPP_IMPL_CODEGEN_ASYNC_GENERIC_SERVICE_H
 
+#include <grpc/impl/codegen/port_platform.h>
+
 #include <grpcpp/impl/codegen/async_stream_impl.h>
 #include <grpcpp/impl/codegen/byte_buffer.h>
 #include <grpcpp/impl/codegen/server_callback_handlers.h>

include/grpcpp/impl/codegen/server_context_impl.h

@@ -24,8 +24,9 @@
 #include <memory>
 #include <vector>
 
-#include <grpc/impl/codegen/compression_types.h>
+#include <grpc/impl/codegen/port_platform.h>
 
+#include <grpc/impl/codegen/compression_types.h>
 #include <grpcpp/impl/codegen/call.h>
 #include <grpcpp/impl/codegen/call_op_set.h>
 #include <grpcpp/impl/codegen/callback_common.h>

include/grpcpp/impl/codegen/server_interface.h

@@ -19,6 +19,8 @@
 #ifndef GRPCPP_IMPL_CODEGEN_SERVER_INTERFACE_H
 #define GRPCPP_IMPL_CODEGEN_SERVER_INTERFACE_H
 
+#include <grpc/impl/codegen/port_platform.h>
+
 #include <grpc/impl/codegen/grpc_types.h>
 #include <grpcpp/impl/codegen/byte_buffer.h>
 #include <grpcpp/impl/codegen/call.h>

include/grpcpp/server_builder_impl.h

@@ -24,6 +24,8 @@
 #include <memory>
 #include <vector>
 
+#include <grpc/impl/codegen/port_platform.h>
+
 #include <grpc/compression.h>
 #include <grpc/support/cpu.h>
 #include <grpc/support/workaround_list.h>

include/grpcpp/server_impl.h

@@ -23,6 +23,8 @@
 #include <memory>
 #include <vector>
 
+#include <grpc/impl/codegen/port_platform.h>
+
 #include <grpc/compression.h>
 #include <grpc/support/atm.h>
 #include <grpcpp/channel_impl.h>