aria2 segfaults on FreeBSD 7.x

This is aria2 0.9.0, but earlier versions
segfault, too.

For example, when run without arguments under
gdb:

<...>
Report bugs to <tujikawa at users dot sourceforge dot net>

Program received signal SIGSEGV, Segmentation fault.
idalloc (ptr=0xa5a5a5a5) at /usr/7/src/lib/libc/stdlib/malloc.c:2950
2950                    malloc_mutex_lock(&chunk->arena->mtx);
Current language:  auto; currently c
(gdb) bt full
#0  idalloc (ptr=0xa5a5a5a5) at /usr/7/src/lib/libc/stdlib/malloc.c:2950
        chunk = (arena_chunk_t *) 0xa5a00000
        __func__ = "idalloc"
#1  0x2858ddbc in free (ptr=0xa5a5a5a5) at
/usr/7/src/lib/libc/stdlib/malloc.c:3628
        __func__ = "free"
#2  0x284efbf9 in operator delete (ptr=0xa5a00000)
    at /usr/7/src/gnu/lib/libstdc++/../../../contrib/libstdc++/libsupc++/del_op.cc:40
No locals.
#3  0x284ecd27 in operator delete[] (ptr=0xa5a5a5a5)
    at /usr/7/src/gnu/lib/libstdc++/../../../contrib/libstdc++/libsupc++/del_opv.cc:36
No locals.
#4  0x08090585 in ~BitfieldMan (this=0x8240130) at BitfieldMan.cc:71
No locals.
#5  0x080dee7d in __tcf_1 () at Peer.h:98
No locals.
#6  0x285d9be2 in __cxa_finalize (dso=0x0) at
/usr/7/src/lib/libc/stdlib/atexit.c:182
        p = (struct atexit *) 0x8210400
        fn = {fn_type = 2, fn_ptr = {std_func = 0x80ded00 <__tcf_1>,
cxa_func = 0x80ded00 <__tcf_1>},
  fn_arg = 0x0, fn_dso = 0x811f004}
        n = 11
#7  0x2858e60e in exit (status=1) at /usr/7/src/lib/libc/stdlib/exit.c:71
No locals.
#8  0x08051325 in main (argc=1, argv=0xbfbfe8b8) at main.cc:702
        optIndex = 0
        lopt = 0
        longOpts = {{name = 0x8117e6b "daemon", has_arg = 0, flag =
0x0, val = 68}, {
    name = 0x8117e72 "dir", has_arg = 1, flag = 0x0, val = 100}, {name
= 0x81183b4 "out", has_arg = 1,
    flag = 0x0, val = 111}, {name = 0x8118077 "log", has_arg = 1, flag
= 0x0, val = 108}, {
    name = 0x8117e76 "split", has_arg = 1, flag = 0x0, val = 115},
{name = 0x81180ff "timeout",
    has_arg = 1, flag = 0x0, val = 116}, {name = 0x8117e7c
"max-tries", has_arg = 1, flag = 0x0,
    val = 109}, {name = 0x8117f10 "http-proxy", has_arg = 1, flag =
0xbfbfe70c, val = 1}, {
    name = 0x8117e86 "http-user", has_arg = 1, flag = 0xbfbfe70c, val = 2}, {
    name = 0x8117e90 "http-passwd", has_arg = 1, flag = 0xbfbfe70c, val = 3}, {
    name = 0x8117e9c "http-proxy-user", has_arg = 1, flag =
0xbfbfe70c, val = 4}, {
    name = 0x8117eac "http-proxy-passwd", has_arg = 1, flag =
0xbfbfe70c, val = 5}, {
    name = 0x8117ebe "http-auth-scheme", has_arg = 1, flag =
0xbfbfe70c, val = 6}, {
    name = 0x8117ecf "referer", has_arg = 1, flag = 0xbfbfe70c, val = 7}, {
    name = 0x8117ed7 "retry-wait", has_arg = 1, flag = 0xbfbfe70c, val = 8}, {
    name = 0x8117ee2 "ftp-user", has_arg = 1, flag = 0xbfbfe70c, val = 9}, {
    name = 0x8117eeb "ftp-passwd", has_arg = 1, flag = 0xbfbfe70c, val = 10}, {
    name = 0x8117ef6 "ftp-type", has_arg = 1, flag = 0xbfbfe70c, val = 11}, {
    name = 0x8117eff "ftp-pasv", has_arg = 0, flag = 0x0, val = 112}, {
    name = 0x8117f08 "ftp-via-http-proxy", has_arg = 1, flag =
0xbfbfe70c, val = 12}, {
    name = 0x8117f1b "http-proxy-method", has_arg = 1, flag =
0xbfbfe70c, val = 14}, {
    name = 0x8117f2d "lowest-speed-limit", has_arg = 1, flag =
0xbfbfe70c, val = 200}, {
    name = 0x8117f40 "max-download-limit", has_arg = 1, flag =
0xbfbfe70c, val = 201}, {
    name = 0x8117f53 "torrent-file", has_arg = 1, flag = 0x0, val = 84}, {
    name = 0x8117f60 "listen-port", has_arg = 1, flag = 0xbfbfe70c, val = 15}, {
    name = 0x8117f6c "follow-torrent", has_arg = 1, flag = 0xbfbfe70c,
val = 16}, {
    name = 0x8117f7b "show-files", has_arg = 0, flag = 0x0, val = 83}, {
    name = 0x8117f86 "no-preallocation", has_arg = 0, flag =
0xbfbfe70c, val = 18}, {
    name = 0x8117f97 "direct-file-mapping", has_arg = 1, flag =
0xbfbfe70c, val = 19}, {
    name = 0x8117fd0 "upload-limit", has_arg = 1, flag = 0xbfbfe70c,
val = 20}, {
    name = 0x8117fab "select-file", has_arg = 1, flag = 0xbfbfe70c, val = 21}, {
    name = 0x8117fb7 "seed-time", has_arg = 1, flag = 0xbfbfe70c, val = 22}, {
    name = 0x8117fc1 "seed-ratio", has_arg = 1, flag = 0xbfbfe70c, val = 23}, {
    name = 0x8117fcc "max-upload-limit", has_arg = 1, flag =
0xbfbfe70c, val = 24}, {
    name = 0x8117fdd "metalink-file", has_arg = 1, flag = 0x0, val = 77}, {
    name = 0x8117feb "metalink-servers", has_arg = 1, flag = 0x0, val = 67}, {
    name = 0x8117ffc "metalink-version", has_arg = 1, flag =
0xbfbfe70c, val = 100}, {
    name = 0x811800d "metalink-language", has_arg = 1, flag =
0xbfbfe70c, val = 101}, {
    name = 0x811801f "metalink-os", has_arg = 1, flag = 0xbfbfe70c,
val = 102}, {
    name = 0x811802b "follow-metalink", has_arg = 1, flag =
0xbfbfe70c, val = 103}, {
    name = 0x811803b "metalink-location", has_arg = 1, flag =
0xbfbfe70c, val = 104}, {
    name = 0x8118005 "version", has_arg = 0, flag = 0x0, val = 118},
{name = 0x811804d "help",
    has_arg = 0, flag = 0x0, val = 104}, {name = 0x0, has_arg = 0,
flag = 0x0, val = 0}}