archival/*: move "config:" snippets into .c files

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

archival/bzip2.c

@@ -7,6 +7,19 @@
  * about bzip2 library code.
  */
 
+//config:config BZIP2
+//config:	bool "bzip2"
+//config:	default y
+//config:	help
+//config:	  bzip2 is a compression utility using the Burrows-Wheeler block
+//config:	  sorting text compression algorithm, and Huffman coding. Compression
+//config:	  is generally considerably better than that achieved by more
+//config:	  conventional LZ77/LZ78-based compressors, and approaches the
+//config:	  performance of the PPM family of statistical compressors.
+//config:
+//config:	  Unless you have a specific application which requires bzip2, you
+//config:	  should probably say N here.
+
 //applet:IF_BZIP2(APPLET(bzip2, BB_DIR_USR_BIN, BB_SUID_DROP))
 //kbuild:lib-$(CONFIG_BZIP2) += bzip2.o