The gettext-full host build might pick up iconv-stub host build headers
during the build, leading to stray linker errors with unresolved references
to libiconv_open(), libiconv() and libiconv_close().
Since we're not needing iconv support on the host, pass the appropriate
cache variables to configure to prevent detection and linking of iconv.
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
b95494baed