darcs patch: Fix detection of libiconf.

Sat Jun 20 14:21:59 CEST 2009 Matthias Kilian * Fix detection of libiconf. It's not enough to try to link against libiconv and look for a symbol iconv_open, because iconv may be installed in a way that internally renames iconv_foo to libiconv_foo in the library and adds corresponding #define iconv_foo libiconv_foo to iconv.h. This patch is needed on OpenBSD (but it's not enough, since cabal suffers from the same problem).