namespaces: add the NAMESPACES config option

The option is selectable if EMBEDDED is chosen only. When the EMBEDDED is off
namespaces will be on.

Signed-off-by: Pavel Emelyanov <[e-mail]>
Acked-by: Serge Hallyn <[e-mail]>
Cc: Cedric Le Goater <[e-mail]>
Cc: "Eric W. Biederman" <[e-mail]>
Cc: Herbert Poetzl <[e-mail]>
Cc: Kirill Korotaev <[e-mail]>
Cc: Sukadev Bhattiprolu <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

init/Kconfig

···
 
 	  If unsure, say N.
 
+config NAMESPACES
+	bool "Namespaces support" if EMBEDDED
+	default !EMBEDDED
+	help
+	  Provides the way to make tasks work with different objects using
+	  the same id. For example same IPC id may refer to different objects
+	  or same user id or pid may refer to different tasks when used in
+	  different namespaces.
+
 config BLK_DEV_INITRD
 	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 	depends on BROKEN || !FRV