m88k: several programs silently exit after signal?

[tsutsui]

ftp(1) exits after SIGALRM? ftp.ktrace.log

    28 ftp      GIO   fd 5 wrote 64 bytes
       "X\M^@\0\0\M-u\M^@X\^W\^T?\0@\^S\^_\08\M-t@X\f\^R\M-_\0000\^R\M^_\0(\^R\
        _\0 \M-t\0\M-D\^Ac\M^?\0`^@\0\^XXr\M-@\240X@\0$\M-L\^A\M^\+X\M^@\0\0\
        \^U\^?\0H"
    28 ftp      PSIG  SIGALRM caught handler=0x16410 mask=())
    28 ftp      GIO   fd 1 read 4 bytes
       "\0\0\0\^\"
    28 ftp      GIO   fd 1 wrote 80 bytes
       "\r  9% |***                                  |   159 KB   98.31 KB/s  \
          00:15 ETA"

emacs-18.59 also exits after SIGIO? emacs.ktrace.log

    46 emacs    GIO   fd 0 read 4 bytes
       "\0\0\0\0"
    46 emacs    PSIG  SIGIO caught handler=0x13890 mask=())
    46 emacs    GIO   fd 0 read 4 bytes
       "\0\0\0\^A"
    46 emacs    GIO   fd 0 read 1 bytes
       " "
    46 emacs    GIO   fd 0 read 4 bytes
       "\0\0\0\0"

[tsutsui]

csh(1) also silently exits after SIGCHLD: csh.ktrace.log

   282 csh      GIO   fd 4 read 512 bytes
       "\0\^B}\M-*\0\f\^D\^A.\0\0\0\0\^B}\M-(\0\f\^D\^B..\0\0\0\^B\^?U\0\^T\b\
        \vemacsclient\0\0\^B\^?V\0\^P\b\^Eetags\0\M->\M-o\0\^B\^?W\0 \b\^Ectag\
        s\0\M->\M-o\0\^B\^?X\0\^P\b\^Fxemacs\0\M-o\0\^B\^?X\^A\M-$\b\^Eemacs\0\
        \M->\M-o\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
        \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"
   282 csh      GIO   fd 4 read 0 bytes
       ""
   282 csh      NAMI  "/usr/bin/id"
   282 csh      GIO   fd 4 read 2 bytes
       "0
       "
   282 csh      GIO   fd 4 read 0 bytes
       ""
   282 csh      PSIG  SIGCHLD caught handler=0x162d0 mask=(2))