bash-2.03# ./apachectl configtest
Syntax error on line 877 of /usr/local/apache/conf/httpd.conf:
Cannot load /usr/local/apache/libexec/libphp4.so into server: ld.so.1: /usr/loca
l/apache/bin/httpd: fatal: relocation error: file /usr/local/apache/libexec/libp
hp4.so: symbol ap_block_alarms: referenced symbol not found

...

 (of course) 

bash-2.03# head -887 ../httpd.conf | tail -1
LoadModule php4_module        /usr/local/apache/libexec/libphp4.so

...

bash-2.03# ldd ../libexec/libphp4.so 
        libdl.so.1 =>    /usr/lib/libdl.so.1
        libpam.so.1 =>   /usr/lib/libpam.so.1
        libfreetype.so.6 =>      /usr/local/lib/libfreetype.so.6
        libpng.so.3 =>   /usr/local/lib/libpng.so.3
        libz.so.1 =>     /usr/lib/libz.so.1
        libcrypt_i.so.1 =>       /usr/lib/libcrypt_i.so.1
        libresolv.so.2 =>        /usr/lib/libresolv.so.2
        libm.so.1 =>     /usr/lib/libm.so.1
        libsocket.so.1 =>        /usr/lib/libsocket.so.1
        libc.so.1 =>     /usr/lib/libc.so.1
        libgcc_s.so.1 =>         /usr/local/lib/libgcc_s.so.1
        libgen.so.1 =>   /usr/lib/libgen.so.1
        libnsl.so.1 =>   /usr/lib/libnsl.so.1
        libmp.so.2 =>    /usr/lib/libmp.so.2
        /usr/platform/SUNW,Ultra-2/lib/libc_psr.so.1

...

 (the only references I could find...)

bash-2.03# grep alarms /tmp/php-4.2.2/*/*/*
/tmp/php-4.2.2/ext/icap/php_icap.c:     PHP_FE(icap_list_alarms,               N
ULL)
/tmp/php-4.2.2/ext/icap/php_icap.c:/* {{{ proto int icap_list_alarms(int stream_
id, array date, array time)
/tmp/php-4.2.2/ext/icap/php_icap.c:   List alarms for a given time */
/tmp/php-4.2.2/ext/icap/php_icap.c:PHP_FUNCTION(icap_list_alarms)
/tmp/php-4.2.2/ext/icap/php_icap.h:PHP_FUNCTION(icap_list_alarms);
/tmp/php-4.2.2/ext/mcal/php_mcal.c:     PHP_FE(mcal_list_alarms,NULL)
/tmp/php-4.2.2/ext/mcal/php_mcal.c:/* {{{ proto bool mcal_list_alarms(int stream
_id, int year, int month, int day, int hour, int min, int sec)
/tmp/php-4.2.2/ext/mcal/php_mcal.c:   List alarms for a given time */
/tmp/php-4.2.2/ext/mcal/php_mcal.c:PHP_FUNCTION(mcal_list_alarms)
/tmp/php-4.2.2/ext/mcal/php_mcal.h:PHP_FUNCTION(mcal_list_alarms);
/tmp/php-4.2.2/sapi/apache/mod_php4.c:  block_alarms();
/tmp/php-4.2.2/sapi/apache/mod_php4.c:  unblock_alarms();
/tmp/php-4.2.2/sapi/apache/mod_php4.c:  block_alarms,                          /
* Block interruptions */
/tmp/php-4.2.2/sapi/apache/mod_php4.c:  unblock_alarms,                        /
* Unblock interruptions */
...

 (fyi)

bash-2.03# bash-2.03# uname -a
SunOS wrench 5.8 Generic_108528-15 sun4u sparc SUNW,Ultra-2
bash-2.03# ./httpd -version
Server version: Apache/1.3.26 (Unix)
Server built:   Aug  4 2002 18:49:32