Description:
------------
We are running php-5.1.6 on solaris 5.9 (sparc64). Since php-5.2.0 all attemts to update failed. A simple echo test works, but almost everything else causes segmentation fault. "make test" stops in the very beginning with "make: [test] Error 139 (ignored)".

Reproduce code:
---------------
$ cat test.php
<?php
echo str_replace("foo", "bar", "foofoo\n");
?>

$ gdb ../sapi/cli/php
GNU gdb 6.3
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GDB is free software, covered by the GNU General Public License, and you are
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Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "sparc-sun-solaris2.8"...
(gdb) set args test.php
(gdb) run
Starting program: /tmp/holder/php-5.2.1/sapi/cli/php test.php
*zval_ptr is null...

Program received signal SIGSEGV, Segmentation fault.
_zval_ptr_dtor (zval_ptr=0xffbfe634) at /tmp/holder/php-5.2.1/Zend/zend_execute_API.c:416
416             (*zval_ptr)->refcount--;
(gdb) backtrace
#0  _zval_ptr_dtor (zval_ptr=0xffbfe634) at /tmp/holder/php-5.2.1/Zend/zend_execute_API.c:416
#1  0x00189b3c in zend_do_fcall_common_helper_SPEC (execute_data=0xffbfe6c8) at zend_execute.h:155
#2  0x00187c40 in execute (op_array=0x2d7da8) at zend_vm_execute.h:92
#3  0x0016c390 in zend_execute_scripts (type=8, retval=Variable "retval" is not available.
) at /tmp/holder/php-5.2.1/Zend/zend.c:1135
#4  0x0012d330 in php_execute_script (primary_file=0xffbfedf0) at /tmp/holder/php-5.2.1/main/main.c:1784
#5  0x001ff870 in main (argc=2, argv=0xffbfee9c) at /tmp/holder/php-5.2.1/sapi/cli/php_cli.c:1114
(gdb) quit

I inserted
    if ((*zval_ptr) == NULL) {
        printf("*zval_ptr is null...\n");
    }
into Zend/zend_execute_API.c, for that the error occurs in line 416 and not in line 412

Actual result:
--------------
Segmentation fault