switch editors/* to embedded-in-source kbuild system

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

editors/diff.c

@@ -76,6 +76,33 @@
  * 6n words for files of length n.
  */
 
+//config:config DIFF
+//config:	bool "diff"
+//config:	default y
+//config:	help
+//config:	  diff compares two files or directories and outputs the
+//config:	  differences between them in a form that can be given to
+//config:	  the patch command.
+//config:
+//config:config FEATURE_DIFF_LONG_OPTIONS
+//config:	bool "Enable long options"
+//config:	default y
+//config:	depends on DIFF && LONG_OPTS
+//config:	help
+//config:	  Enable use of long options.
+//config:
+//config:config FEATURE_DIFF_DIR
+//config:	bool "Enable directory support"
+//config:	default y
+//config:	depends on DIFF
+//config:	help
+//config:	  This option enables support for directory and subdirectory
+//config:	  comparison.
+
+//kbuild:lib-$(CONFIG_DIFF) += diff.o
+
+//applet:IF_DIFF(APPLET(diff, BB_DIR_USR_BIN, BB_SUID_DROP))
+
 //usage:#define diff_trivial_usage
 //usage:       "[-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"
 //usage:#define diff_full_usage "\n\n"