uClibc's iconv.h is just broken, so switch iconv off for now.

Did you know that uClibc has an include/iconv.h in the source that has
a line "#error Attempted to include iconv.h when uClibc was built without
locale support." And then in the top level Makefile it has
"Makefile.in:HEADERS_RM-$(UCLIBC_HAS_LOCALE) += iconv.h bits/uClibc_ctype.h"
so that file is deleted after being installed in the case that line would
trigger. So it implements things it then prevents from ever being used.

The correct answer this this insanity is to switch to musl. Working on it...

diff -ru toybox/toys/pending/iconv.c toybox.bak/toys/pending/iconv.c
--- toybox/toys/pending/iconv.c	2014-04-16 19:49:15.000000000 -0500
+++ toybox.bak/toys/pending/iconv.c	2014-09-06 10:52:43.195279885 -0500
@@ -8,7 +8,7 @@
 
 config ICONV
   bool "iconv"
-  default y
+  default n
   help
     usage: iconv [-f FROM] [-t TO] [FILE...]