What I did:

Compiled 4.3.2RC1 on my Sun Ultra10/Sparc64 NetBSD 1.6.

Used:
./configure --enable-debug --with-apxs --with-session=shared,/usr/pkg/lib/php/20
020429  --with-gettext=shared,/usr/pkg/lib/php/20020429 --with-pcre=shared,/usr/
pkg/lib/php/20020429

Ran make test and one of the tests that failed follows:

Segmentation fault - core dumped
FAIL Bug #22510 (segfault among complex references) [tests/lang/bug22510.phpt]

So, I ran gdb and the backtrace follows:

gdb
GNU gdb 5.0nb1
Copyright 2000 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "sparc64--netbsd".
(gdb) file sapi/cli/php
Reading symbols from sapi/cli/php...done.
(gdb) r tests/lang/bug22510.phpt
Starting program: /usr/home/mlm/php-4.3.2RC1/sapi/cli/php tests/lang/bug22510.ph
pt
--TEST--
Bug #22510 (segfault among complex references)
--FILE--
ok1
bar::run1
foo::method1
foo::method1
foo::finalize
done!
ok2
bar::run2
foo::method2
foo::method2
foo::finalize
done!
ok3
bar::run3
foo::method3
foo::method3
foo::finalize
done!
ouch
bar::run1
foo::method1
foo::method1
foo::finalize
[Mon Mar 31 19:20:58 2003]  Script:  'tests/lang/bug22510.phpt'
---------------------------------------
/usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c(271) : Block 0x00442140 status:
Beginning:      Overrun (magic=0x00000000, expected=0x7312F8DC)

Program received signal SIGSEGV, Segmentation fault.
0x40779970 in bcopy () from /usr/lib/libc.so.12
(gdb) bt
#0  0x40779970 in bcopy () from /usr/lib/libc.so.12
#1  0x2a0c60 in _mem_block_check (ptr=0x442180, silent=0, 
    __zend_filename=0x311e78 "/usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c", 
    __zend_lineno=271, __zend_orig_filename=0x0, __zend_orig_lineno=0)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_alloc.c:649
#2  0x2a0c14 in _mem_block_check (ptr=0x442180, silent=1, 
    __zend_filename=0x311e78 "/usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c", 
    __zend_lineno=271, __zend_orig_filename=0x0, __zend_orig_lineno=0)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_alloc.c:641
#3  0x29f3cc in _efree (ptr=0x442180, 
    __zend_filename=0x311e78 "/usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c", 
    __zend_lineno=271, __zend_orig_filename=0x0, __zend_orig_lineno=0)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_alloc.c:217
#4  0x2d42d4 in zend_assign_to_variable_reference (result=0x4c0408, 
    variable_ptr_ptr=0x4c7658, value_ptr_ptr=0x4ae658, Ts=0xffffffffffffaa50)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c:271
#5  0x2d960c in execute (op_array=0x4b7c40)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c:1354
#6  0x2dae3c in execute (op_array=0x4b7040)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend_execute.c:1650
#7  0x2be5dc in zend_execute_scripts (type=8, retval=0x0, file_count=3)
    at /usr/home/mlm/php-4.3.2RC1/Zend/zend.c:864
#8  0x261a14 in php_execute_script (primary_file=0xffffffffffffd950)
---Type <return> to continue, or q <return> to quit---
    at /usr/home/mlm/php-4.3.2RC1/main/main.c:1636
#9  0x2e3f00 in main (argc=2, argv=0xffffffffffffdae8)
    at /usr/home/mlm/php-4.3.2RC1/sapi/cli/php_cli.c:753
#10 0x12429c in ___start ()
(gdb) quit

Trying desprately to find a release that works on Sparc64,

So, let me know what I can do to help debug this,

Thank You,
Mike Marshall