Convert all util-linux/* applets to "new style" applet definitions

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

util-linux/umount.c

@@ -7,6 +7,26 @@
  *
  * Licensed under GPLv2, see file LICENSE in this source tree.
  */
+//config:config UMOUNT
+//config:	bool "umount"
+//config:	default y
+//config:	select PLATFORM_LINUX
+//config:	help
+//config:	  When you want to remove a mounted filesystem from its current mount
+//config:	  point, for example when you are shutting down the system, the
+//config:	  'umount' utility is the tool to use. If you enabled the 'mount'
+//config:	  utility, you almost certainly also want to enable 'umount'.
+//config:
+//config:config FEATURE_UMOUNT_ALL
+//config:	bool "Support option -a"
+//config:	default y
+//config:	depends on UMOUNT
+//config:	help
+//config:	  Support -a option to unmount all currently mounted filesystems.
+
+//applet:IF_UMOUNT(APPLET(umount, BB_DIR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_UMOUNT) += umount.o
 
 //usage:#define umount_trivial_usage
 //usage:       "[OPTIONS] FILESYSTEM|DIRECTORY"