Haiku needs to link against libiconv, not libtextencoding (solves linker issue...

Haiku needs to link against libiconv, not libtextencoding (solves linker issue when building cudatext)

This isn't my own patch but has been sitting around at our haikuports repository, I need to change this when building fpc/lazarus with fpcupdeluxe everytime I try to update, would be nice if this could be fixed upstream.

Thanks in advance.