5704 libzfs can only handle 255 filedescriptors

*** 622,638 ****
          if ((hdl->libzfs_fd = open(ZFS_DEV, O_RDWR)) < 0) {
                  free(hdl);
                  return (NULL);
          }
  
!         if ((hdl->libzfs_mnttab = fopen(MNTTAB, "r")) == NULL) {
                  (void) close(hdl->libzfs_fd);
                  free(hdl);
                  return (NULL);
          }
  
!         hdl->libzfs_sharetab = fopen("/etc/dfs/sharetab", "r");
  
          if (libzfs_core_init() != 0) {
                  (void) close(hdl->libzfs_fd);
                  (void) fclose(hdl->libzfs_mnttab);
                  (void) fclose(hdl->libzfs_sharetab);
--- 622,638 ----
          if ((hdl->libzfs_fd = open(ZFS_DEV, O_RDWR)) < 0) {
                  free(hdl);
                  return (NULL);
          }
  
!         if ((hdl->libzfs_mnttab = fopen(MNTTAB, "rF")) == NULL) {
                  (void) close(hdl->libzfs_fd);
                  free(hdl);
                  return (NULL);
          }
  
!         hdl->libzfs_sharetab = fopen("/etc/dfs/sharetab", "rF");
  
          if (libzfs_core_init() != 0) {
                  (void) close(hdl->libzfs_fd);
                  (void) fclose(hdl->libzfs_mnttab);
                  (void) fclose(hdl->libzfs_sharetab);