lib/vfio_user: move client vfio_user library into child directory

vfio_user/host is the PCI abstraction over vfio-user transport, it's
client library. We will add a target library to emulate PCI devices
in next patch, so new lib/vfio_user contains two libraries, one
is for host, the other one is for target.

Change-Id: I9bb40043105525654360691d6db62e4958384e7f
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12314
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Dong Yi <dongx.yi@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

lib/vfio_user/Makefile

@@ -34,12 +34,11 @@
 SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
-SO_VER := 3
-SO_MINOR := 0
+DIRS-y += host
 
-C_SRCS = vfio_user_pci.c vfio_user.c
-LIBNAME = vfio_user
+.PHONY: all clean $(DIRS-y)
 
-SPDK_MAP_FILE = $(abspath $(CURDIR)/spdk_vfio_user.map)
+all: $(DIRS-y)
+clean: $(DIRS-y)
 
-include $(SPDK_ROOT_DIR)/mk/spdk.lib.mk
+include $(SPDK_ROOT_DIR)/mk/spdk.subdirs.mk

lib/vfio_user/host/Makefile

@@ -0,0 +1,45 @@
+#
+#  BSD LICENSE
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in
+#      the documentation and/or other materials provided with the
+#      distribution.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+
+SO_VER := 3
+SO_MINOR := 0
+
+C_SRCS = vfio_user_pci.c vfio_user.c
+LIBNAME = vfio_user
+
+SPDK_MAP_FILE = $(abspath $(CURDIR)/spdk_vfio_user.map)
+
+include $(SPDK_ROOT_DIR)/mk/spdk.lib.mk