The following script crashes php

<?php
$arr[0] = 1;
$arr = array_merge($arr, array(2, 3, 4));
var_dump($arr);
?>

Here is the output and backtrace

[steinm@steinpb DatenbankLayout]$ php -f test.php 
array(4) {
  [0]=>
  int(1)
 [1]=>
 int(2)
 [2]=>
 int(3)
Speicherzugriffsfehler (core dumped)
[steinm@steinpb DatenbankLayout]$ gdb -f /usr/local/bin/php
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This GDB was configured as "ppc-redhat-linux"...
(gdb) run -f test.php
Starting program: /usr/local/bin/php -f test.php
array(4) {
  [0]=>
  int(1)
 [1]=>
 int(2)
 [2]=>
 int(3)

Program received signal SIGSEGV, Segmentation fault.
0xfc452e8 in vfprintf () at vfprintf.c:1565
1565	vfprintf.c: Datei oder Verzeichnis nicht gefunden.
(gdb) bt
#0  0xfc452e8 in vfprintf () at vfprintf.c:1565
#1  0xfc55ef0 in _IO_vsnprintf (string=0x7fffd660 "", maxlen=4096, 
    format=0x1011e9a8 "%*c[%ld]=>\n", args=0x7fffd650) at vsnprintf.c:129
#2  0x1001b0d4 in php_printf (format=0x30015001 "int(3)\n\n{\n") at main.c:327
#3  0x100aaf18 in php_array_element_dump (zv=0x1019893c, num_args=269609384, 
    args=0x30015001, hash_key=0xfcf114c) at var.c:48
#4  0x100d6210 in zend_hash_apply_with_arguments (ht=0x10198828, 
    destruct=0x100aaea4 <php_array_element_dump>, num_args=1)
    at zend_hash.c:737
#5  0x100ab220 in php_var_dump (struc=0x10198828, level=1) at var.c:93
#6  0x100ab374 in php_if_var_dump (ht=0, return_value=0x1011e9a8, 
    this_ptr=0x30015001, return_value_used=265228620) at var.c:131
#7  0x10105da4 in execute (op_array=0x10194098) at ./zend_execute.c:1519
#8  0x100d1720 in zend_execute_scripts (type=0, file_count=3) at zend.c:729
#9  0x1001ca94 in php_execute_script (primary_file=0x7ffffb58) at main.c:1210
#10 0x1001a8d4 in main (argc=3, argv=0x7ffffc54) at cgi_main.c:741
(gdb)