Was able to get some output from gdb.  This is not the debug build, but built with -g to gcc.

(gdb) cont
Continuing.
[New Thread 12 (LWP 4)]
[Switching to Thread 12 (LWP 4)]

Program received signal SIGSEGV, Segmentation fault.
0xfed34434 in thr_getspecific () from /usr/lib/libthread.so.1
(gdb) bt
#0  0xfed34434 in thr_getspecific () from /usr/lib/libthread.so.1
Cannot access memory at address 0xfde41f44

Was able to get some output from gdb.  This is not the debug build, but built with -g to gcc.

(gdb) cont
Continuing.
[New Thread 12 (LWP 4)]
[Switching to Thread 12 (LWP 4)]

Program received signal SIGSEGV, Segmentation fault.
0xfed34434 in thr_getspecific () from /usr/lib/libthread.so.1
(gdb) bt
#0  0xfed34434 in thr_getspecific () from /usr/lib/libthread.so.1
Cannot access memory at address 0xfde41f44

Can you please try the latest snapshot available at snaps.php.net or even better the latest CVS (make sure you grab the latest CVS of TSRM if you use CVS).

Compile failed using php4-200104200645:

Making all in oci8
/bin/sh /usr/share/src/php4-200104200645/libtool --silent --mode=compile gcc  -I. -I/usr/share/src/php4-200104200645/ext/oci8 -I/usr/share/src/php4-200104200645/main -I/usr/share/src/php4-200104200645 -I/opt/NetScape/server4/plugins/include -I/usr/share/src/php4-200104200645/Zend -I/usr/share/src/php4-200104200645/ext/mysql/libmysql -I/opt/Oracle/rdbms/demo -I/opt/Oracle/network/public -I/opt/Oracle/plsql/public -I/usr/share/src/php4-200104200645/ext/xml/expat/xmltok -I/usr/share/src/php4-200104200645/ext/xml/expat/xmlparse -I/usr/share/src/php4-200104200645/TSRM  -D_POSIX_PTHREAD_SEMANTICS -D_POSIX_PTHREAD_SEMANTICS -D_REENTRANT -DSUPPORT_UTF8 -DXML_BYTE_ORDER=21 -I../TSRM -DTHREAD=1 -g -O2 -pthreads  -c oci8.c
oci8.c: In function `php_if_ocicollappend':
oci8.c:4361: `oci_globals' undeclared (first use in this function)
oci8.c:4361: (Each undeclared identifier is reported only once
oci8.c:4361: for each function it appears in.)
oci8.c: In function `php_if_ocicolldategetelem':
oci8.c:4485: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicolldateassignelem':
oci8.c:4595: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicolldateappendelem':
oci8.c:4689: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicollgetelem':
oci8.c:4741: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicollassign':
oci8.c:4828: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicollassignelem':
oci8.c:4889: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicollsize':
oci8.c:4972: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicollmax':
oci8.c:4994: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocicolltrim':
oci8.c:5020: `oci_globals' undeclared (first use in this function)
oci8.c: In function `php_if_ocinewcollection':
oci8.c:5062: `oci_globals' undeclared (first use in this function)
*** Error code 1
make: Fatal error: Command failed for target `oci8.lo'
Current working directory /usr/share/src/php4-200104200645/ext/oci8
*** Error code 1
make: Fatal error: Command failed for target `all-recursive'
Current working directory /usr/share/src/php4-200104200645/ext/oci8
*** Error code 1
make: Fatal error: Command failed for target `all-recursive'
Current working directory /usr/share/src/php4-200104200645/ext
*** Error code 1
make: Fatal error: Command failed for target `all-recursive'

I've been able to DL and compile 4.0.5.  Now Iplanet will not start with PHP enabled.  Relevant obj.conf lines:

Init fn="load-modules" funcs="php4_init,php4_close,php4_execute,php4_auth_trans" shlib="/
opt/NetScape/server4/bin/libphp4.so"
Init fn="php4_init" errorString="Failed to Initialize PHP!"

Service method="(GET|HEAD|POST)" type="magnus-internal/x-httpd-php" fn="php4_execute"

<Object name="x-httpd-php">
ObjectType fn="force-type" type="magnus-internal/x-httpd-php"
Service fn="php4_execute"
</Object>

Last few lines of truss of process:

23555:  door_info(7, 0xFFBEE7A8)                        = 0
23555:  getpid()                                        = 23555 [23554]
23555:  door_call(7, 0xFFBEE790)                        = 0
23555:  close(7)                                        = 0
23554:  signotifywait()                                 = 17
23554:      Received signal #17, SIGUSR2, in sigsuspend() [caught]
23554:        siginfo: SIGUSR2 pid=23555 uid=16
23554:  lwp_sigredirect(1, SIGUSR2)                     = 0
23554:  sigsuspend(0xFFBEF3F0)                          Err#4 EINTR
23554:  sysconfig(_CONFIG_SIGRT_MIN)                    = 38
23554:  sigprocmask(SIG_SETMASK, 0xFEFBDAE0, 0x00000000) = 0
23554:  sigprocmask(SIG_SETMASK, 0xFEFC9810, 0x00000000) = 0
23554:  sysconfig(_CONFIG_SIGRT_MIN)                    = 38
23554:  setcontext(0xFFBEECE0)
23554:  sigprocmask(SIG_SETMASK, 0xFFBEF380, 0x00000000) = 0
23554:  llseek(0, 0, SEEK_CUR)                          = 165404
23554:  _exit(1)
23557:          *** process killed ***
23555:  unlink("/opt/NetScape/server4/https-itjs44.iss.net/logs/pid") = 0
23555:  fstat(4, 0xFFBEF2C0)                            = 0
23555:  close(4)                                        = 0
23555:  llseek(0, 0, SEEK_CUR)                          = 165625

Thank you for taking the time to report a problem with PHP.
Unfortunately you are not using a current version of PHP -- 
the problem might already be fixed. Please download a new
PHP version from http://www.php.net/downloads.php

If you are able to reproduce the bug with one of the latest
versions of PHP, please change the PHP version on this bug report
to the version you tested and change the status back to "Open".
Again, thank you for your continued support of PHP.