I tried to configure PHP like this:

#!/bin/sh

./configure --with-mysql --with-apache=../apache_1.3.12 \
        --enable-track-vars --enable-calendar                   \
        --with-mod_charset --with-servlet                       \
        --with-config-file-path=/etc/php4/apache                \
        --with-gdbm=/usr --with-db2                             \
        --enable-ftp                                            \
        --with-ldap --with-pgsql                        \
        --with-readline --enable-trans-sid --with-openssl       \
        --enable-sockets --enable-sysvsem --enable-sysvshm      \
        --enable-versioning --with-gnu-ld


(actually, this is a cut&paste from a small shell script
so I don't have to type this in anytime I run configure)




Running this in a pristine directory, created by
tar xzvf php-4.0.2.tar.gz, results in (lots of
messages clipped):

...
checking for isnan... no
checking whether fp_except is defined... no
checking whether to enable C9x-inline semantics... no
checking whether to enable experimental ZTS... yes
checking whether to enable inline optimization for GCC... no
checking whether to enable a memory limit... no
checking whether to enable Zend debugging... no
checking for c++... c++
checking whether the C++ compiler (c++   -Wl,-rpath,/lib -L/lib) works... no
configure: error: installation or configuration problem: C++ compiler cannot create executables.


Of course this is not true, and at some point I had
it also compile cleanly after mangling the ./configure,
but I'm no expert at that, and it broke soon afterwards.