* 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.