isatty: Make it return true in Cygwin consoles on native Windows. * lib/isatty.c: Include <string.h>. (GetProcAddress): New macro. (GetNamedPipeClientProcessIdFuncType): New type. (GetNamedPipeClientProcessIdFunc): New variable. (QueryFullProcessImageNameFuncType): New type. (QueryFullProcessImageNameFunc): New variable. (initialized): New variable. (initialize): New function. (IsCygwinConsoleHandle): New function. (isatty): Invoke it. * doc/posix-functions/isatty.texi: Mention the issue.

#ifndef USERSPEC_H
# define USERSPEC_H 1

# include <sys/types.h>

const char *
parse_user_spec (const char *spec_arg, uid_t *uid, gid_t *gid,
                 char **username_arg, char **groupname_arg);

#endif