When building against kfw (tested with 3.2.0), typical autoconf macros
are "leaked" into the client application from the include of win-mac.h.
For example, HAVE_NETINET_IN_H, HAVE_STRING_H and HAVE_STRDUP. This
causes redefinition warnings for other programs that use autoconf for
their own local configuration.

These defines should not be leaked into the public namespace that's
included when just including krb5.h or gssapi.h.