Using array_sum() on an undefined causes php to core dump.

uname:
Linux redbox 2.2.17-14enterprise #1 SMP Mon Feb 5 18:31:31 EST 2001 i686 unknown

configure:
'./configure' '--with-apache=../apache_1.3.19' '--enable-gd-imgstrttf' '--with-gd' '--with-ttf' '--with-ldap' '--with-mysql=/usr' '--with-readline' '--enable-sysvsem' '--enable-sysvshm' '--enable-shmop' '--with-zlib' '--with-imap' '--with-imap-ssl' '--with-kerberos' '--with-oracle=/opt/oracle/8.1.7' '--with-oci8=/opt/oracle/8.1.7' '--with-gdbm' '--enable-dbase' '--with-snmp' '--enable-ucd-snmp-hack' '--with-gettext' '--enable-track-vars' '--enable-versioning' '--enable-ftp' '--enable-bcmath' '--with-pgsql' '--enable-calendar'

[root@redbox address_book]# ls -l test.php 
-rwxr-xr-x    1 root     root           50 Apr 18 16:54 test.php
[root@redbox address_book]# cat test.php 
#!/usr/local/bin/php -q
<? echo array_sum($a); ?>
[root@redbox address_book]# ./test.php 
Segmentation fault (core dumped)

If $a is defined this doesn't happen:

[root@redbox address_book]# cat test.php 
#!/usr/local/bin/php -q
<? $a[]=''; echo array_sum($a); ?>
[root@redbox address_book]# ./test.php 
0