component/libiconv: upgrade to 1.17

libiconv 1.14 doesn't compile on aarch64 with the following error:
configure: error: cannot guess build type; you must specify one

See merge request nexedi/slapos!1317

component/libiconv/buildout.cfg

 [buildout]
-extends =
-  ../patch/buildout.cfg
 parts =
   libiconv
 
 [libiconv]
-patch-binary = ${patch:location}/bin/patch
-patch-options = -p1
-patches =
-  ${:_profile_base_location_}/libiconv.gets.patch#8a20d8afe0617fce56f77537d2b84621
 recipe = slapos.recipe.cmmi
 shared = true
-url = http://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.14.tar.gz
-md5sum = e34509b1623cec449dfeb73d7ce9c6c6
+url = http://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.17.tar.gz
+md5sum = d718cd5a59438be666d1575855be72c3

component/libiconv/libiconv.gets.patch

---- libiconv-1.14.orig/srclib/stdio.in.h        2011-08-07 13:42:06.000000000 +0000
-+++ libiconv-1.14/srclib/stdio.in.h     2013-01-09 19:56:21.115819812 +0000
-@@ -680,22 +680,7 @@
- #endif
- 
- #if @GNULIB_GETS@
--# if @REPLACE_STDIO_READ_FUNCS@ && @GNULIB_STDIO_H_NONBLOCKING@
--#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
--#   undef gets
--#   define gets rpl_gets
--#  endif
--_GL_FUNCDECL_RPL (gets, char *, (char *s) _GL_ARG_NONNULL ((1)));
--_GL_CXXALIAS_RPL (gets, char *, (char *s));
--# else
--_GL_CXXALIAS_SYS (gets, char *, (char *s));
--#  undef gets
--# endif
--_GL_CXXALIASWARN (gets);
--/* It is very rare that the developer ever has full control of stdin,
--   so any use of gets warrants an unconditional warning.  Assume it is
--   always declared, since it is required by C89.  */
--_GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
-+#undef gets
- #endif