* cygwin.din: Export __check_rhosts_file, __rcmd_errstr, optarg,
opterr, optind, optopt, optreset, getopt, getopt_long, iruserok
and ruserok.
* getopt.c: Moved from lib to here. Define opt* variables as
dllexport.
* iruserok.c: Moved from lib to here. Rearrange function order.
Prefer using 64/32 bit functions.
* syscalls.cc (shell_fp): Define as struct __sFILE64.
(getusershell): Use fopen64 instead of fopen.
* winsup.h: Add declarations for seteuid32, fopen64,
cygwin_gethostbyname and cygwin_inet_addr.
* include/getopt.h: Declare opt* variables dllimport.
* include/cygwin/version.h: Bump API minor number.