The libgnomevfs/gnome-vfs-resolve.c has a switch case in the _gnome_vfs_result_from_gai_error that converts the given error number to an appropriate gnome-vfs error code.  However, there is a little problem when handling EAI_ADDRFAMILY, hidden by the #ifdef "pollution".

Consider a system that has EAI_ADDRFAMILY but lacks EAI_NODATA.  In that situation, the EAI_ADDRFAMILY case will fall through EAI_SYSTEM, returning a non-sense value.  Or, e.g. if EAI_SYSTEM is not available, then the code will fall through to EAI_AGAIN, returning that there was a name server error.  Similarly, if EAI_NODATA is available, the code will return that there is no address (or whatever the error means, I do not know exactly).

Summarizing: given that many entries of that switch construction are conditionally built, EAI_ADDRFAMILY should explicitly return its appropriate error value so that it does not depend on the other macros being defined.

If I understood it correctly, an EAI_ADDRFAMILY error should be converted to GNOME_VFS_ERROR_HOST_HAS_NO_ADDRESS.  If so, this is what the attached patch does.