illumos gate

Issue found by gcc 7 build:

    ../help.c:88:2: error: this statement may fall through [-Werror=implicit-fallthrough=]
      ss_page_stdin();
      ^~~~~~~~~~~~~~~
    ../help.c:89:5: note: here
         default:
         ^~~~~~~

    ../pager.c:55:3: error: this statement may fall through [-Werror=implicit-fallthrough=]
       ss_page_stdin();
       ^~~~~~~~~~~~~~~
    ../pager.c:56:2: note: here
      default:
      ^~~~~~~

    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:177:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:178:3: note: here
       case 7:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:179:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:180:3: note: here
       case 6:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:181:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:182:3: note: here
       case 5:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:183:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:184:3: note: here
       case 4:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:185:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:186:3: note: here
       case 3:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:187:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:188:3: note: here
       case 2:
       ^~~~
    ../hash/hash_func.c:166:20: error: this statement may fall through [-Werror=implicit-fallthrough=]
     #define HASH4b   h = (h << 5) + h + *k++;
                      ~~^~~~~~~~~~~~~~~~~~~~
    ../hash/hash_func.c:167:15: note: in expansion of macro 'HASH4b'
     #define HASH4 HASH4b
                   ^~~~~~
    ../hash/hash_func.c:189:5: note: in expansion of macro 'HASH4'
         HASH4;
         ^~~~~
    ../hash/hash_func.c:190:3: note: here
       case 1:
       ^~~~

    ../kdb_db2.c:292:5: error: this statement may fall through [-Werror=implicit-fallthrough=]
      if (db != NULL)
         ^
    ../kdb_db2.c:294:5: note: here
         default:
         ^~~~~~~
    ../kdb_db2.c: In function 'krb5_db2_db_get_principal':
    ../kdb_db2.c:1006:9: error: this statement may fall through [-Werror=implicit-fallthrough=]
      retval = 0;
      ~~~~~~~^~~
    ../kdb_db2.c:1008:5: note: here
         case -1:
         ^~~~
    ../kdb_db2.c: In function 'krb5_db2_db_delete_principal':
    ../kdb_db2.c:1222:9: error: this statement may fall through [-Werror=implicit-fallthrough=]
      retval = KRB5_KDB_NOENTRY;
    ../kdb_db2.c:1224:5: note: here
         case -1:
         ^~~~

    ../adb_openclose.c:297:9: error: this statement may fall through [-Werror=implicit-fallthrough=]
        perm = 1;
        ~~~~~^~~
    ../adb_openclose.c:299:2: note: here
      case KRB5_DB_LOCKMODE_EXCLUSIVE:
      ^~~~
    ../adb_openclose.c: In function 'osa_adb_open_and_lock':
    ../adb_openclose.c:413:7: error: this statement may fall through [-Werror=implicit-fallthrough=]
        if (db->db != NULL)
           ^
    ../adb_openclose.c:415:6: note: here
          default:
          ^~~~~~~

    cc1: all warnings being treated as errors