9696 add /etc/system.d support
Portions contributed by: Andy Fiddaman <andy@omniosce.org>
Reviewed by: Hans Rosenfeld <hans.rosenfeld@joyent.com>
Reviewed by: Peter Tribble <peter.tribble@gmail.com>
Reviewed by: C Fraire <cfraire@me.com>
Reviewed by: Toomas Soome <tsoome@me.com>

*** 3349,3359 ****
          intptr_t fd;
  
          if ((fd = kobj_open(systemfile)) != -1L)
                  kobj_close(fd);
          else
!                 systemfile = NULL;
  
          /*CONSTANTCONDITION*/
          while (1) {
                  printf("Name of system file [%s]:  ",
                      systemfile ? systemfile : "/dev/null");
--- 3349,3359 ----
          intptr_t fd;
  
          if ((fd = kobj_open(systemfile)) != -1L)
                  kobj_close(fd);
          else
!                 systemfile = self_assembly = NULL;
  
          /*CONSTANTCONDITION*/
          while (1) {
                  printf("Name of system file [%s]:  ",
                      systemfile ? systemfile : "/dev/null");
*** 3361,3376 ****
                  console_gets(s0, sizeof (s0));
  
                  if (s0[0] == '\0')
                          break;
                  else if (strcmp(s0, "/dev/null") == 0) {
!                         systemfile = NULL;
                          break;
                  } else {
                          if ((fd = kobj_open(s0)) != -1L) {
                                  kobj_close(fd);
                                  systemfile = s0;
                                  break;
                          }
                  }
                  printf("can't find file %s\n", s0);
          }
--- 3361,3377 ----
                  console_gets(s0, sizeof (s0));
  
                  if (s0[0] == '\0')
                          break;
                  else if (strcmp(s0, "/dev/null") == 0) {
!                         systemfile = self_assembly = NULL;
                          break;
                  } else {
                          if ((fd = kobj_open(s0)) != -1L) {
                                  kobj_close(fd);
                                  systemfile = s0;
+                                 self_assembly = NULL;
                                  break;
                          }
                  }
                  printf("can't find file %s\n", s0);
          }