+ Portability fixes prompted by Bernd Eckenfels, the Debian maintainer:
+ * Correct type of various printf arguments: ptrdiff_t != int.
+ * Do not print size of leaked blocks of memory (this causes
+ a spurious regression test failure on some platforms).
+ * Provide adns_if_none and adns_qf_none (which will help with compilers
+ which complain about plain `0' being passed where an enum is wanted).
+ * adnstest converts some errno values to EFOOBAR: all of the ones
+ mentioned in adns.h, at least. This makes the regression test
+ more portable (fixes problem noticed by Bernd Eckenfels).
+ * Add -Wno-pointer-sign if GCC has that option.