samples: mei: build sample program for target architecture

This userspace program includes UAPI headers exported to usr/include/.
'make headers' always works for the target architecture (i.e. the same
architecture as the kernel), so the sample program should be built for
the target as well. Kbuild now supports 'userprogs' for that.

I also guarded the CONFIG option by 'depends on CC_CAN_LINK' because
$(CC) may not provide libc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>

samples/Kconfig

@@ -193,6 +193,7 @@ config SAMPLE_VFS
 config SAMPLE_INTEL_MEI
 	bool "Build example program working with intel mei driver"
 	depends on INTEL_MEI
+	depends on CC_CAN_LINK && HEADERS_INSTALL
 	help
 	  Build a sample program to work with mei device.
 

samples/mei/Makefile

 # SPDX-License-Identifier: GPL-2.0
 # Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
 
-hostprogs := mei-amt-version
+userprogs := mei-amt-version
+always-y := $(userprogs)
 
-HOSTCFLAGS_mei-amt-version.o += -I$(objtree)/usr/include
-
-always-y := $(hostprogs)
-
-all: mei-amt-version
+userccflags += -I usr/include