LG

Dear,

By fuzzing, I found that this file makes dot
(from git 3a83759e870904f0fb22de0b4e31cc86938e8c89) crash.

FICHIER

gdb backtrace:
```
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#1  0x00007ffff6dfb1f1 in __GI_abort () at abort.c:79
#2  0x00007ffff6df1288 in __assert_fail_base (
    fmt=0x7ffff6f59218 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", 
    assertion=assertion@entry=0x7ffff7fd79c3 "bz.size > 0", 
    file=file@entry=0x7ffff7fd79b6 "emit.c", line=line@entry=3970, 
    function=function@entry=0x7ffff7fd7f70 <__PRETTY_FUNCTION__.9500> "bezier_bb
#3  0x00007ffff6df1306 in __GI___assert_fail (
    assertion=assertion@entry=0x7ffff7fd79c3 "bz.size > 0", 
    file=file@entry=0x7ffff7fd79b6 "emit.c", line=line@entry=3970, 
    function=function@entry=0x7ffff7fd7f70 <__PRETTY_FUNCTION__.9500> "bezier_bb
#4  0x00007ffff7f74403 in bezier_bb (bz=...) at emit.c:3970
#5  0x00007ffff7f9a7bf in init_splines_bb (spl=0x555555833860) at emit.c:3998
#6  init_bb_edge (e=0x555555590a90) at emit.c:4023
#7  init_bb_node (n=0x555555589fa0, g=0x55555557c6e0) at emit.c:4040
#8  init_bb (g=0x55555557c6e0) at emit.c:4056
#9  gvRenderJobs (gvc=0x5555555599b0, g=0x55555557c6e0) at emit.c:4110
#10 0x00005555555557ce in main (argc=2, argv=0x7fffffffd7f8) at dot.c:133
```

valgrind:
```
==27903== 
==27903== Process terminating with default action of signal 6 (SIGABRT): dumping
==27903==    at 0x56BA9CA: raise (raise.c:51)
==27903==    by 0x56BC1F0: abort (abort.c:79)
==27903==    by 0x56B2287: __assert_fail_base (assert.c:92)
==27903==    by 0x56B2305: __assert_fail (assert.c:101)
==27903==    by 0x4184402: ??? (in .../graphviz/gr
==27903==    by 0x41AA7BE: ??? (in .../graphviz/gr
==27903==    by 0x1097CD: ??? (in .../graphviz/gra
==27903==    by 0x56A5AFE: (below main) (libc-start.c:308)
==27903== 
```