* cygwin.din: Add symbol hstrerror.

* net.cc: Change meaning of member `s' of struct host_errmap.
        (set_host_errno): Fix error in loop condition.
        (hstrerror): Ditto.
        (herror): Add appropriate functionality.
        * include/netdb.h: Add declaration of hstrerror.
        * include/cygwin/version.h: Bump CYGWIN_VERSION_API_MINOR to 29.

winsup/cygwin/include/netdb.h

@@ -151,6 +151,7 @@ struct servent	*getservent (void);
 struct rpcent	*getrpcent (void);
 struct rpcent	*getrpcbyname (const char *);
 struct rpcent	*getrpcbynumber (int);
+const char      *hstrerror (int);
 void		herror (const char *);
 void		sethostent (int);
 void		setnetent (int);