Installation when Apache is not in /usr/local

I'm trying to install PHP on my own webserver that's installed in a
nonstandard directory on a university server, following these instructions:
http://www.php.net/manual/en/install.unix.apache2.php I already had Apache
installed and working before I started. I don't need MySQL, and Apache is
running from inside my home directory, so in Step 5, I changed this line:

./configure --with-apxs2=/usr/local/apache2/bin/apxs --with-mysql


to

./configure --with-apxs2=/home/where/it/really/is/bin/apxs


That appeared to work, so then I ran "make," which took a very long time.
Then I tried the next step, "make install," and got all this:

Installing PHP SAPI module:       apache2handler
/usr/local/pkg/apache/2.2.8/build/instdso.sh
SH_LIBTOOL='/usr/local/pkg/apache/2.2.8/build/libtool'
libphp5.la/usr/local/pkg/apache/2.2.8/modules
/usr/local/pkg/apache/2.2.8/build/libtool --mode=install cp
libphp5.la/usr/local/pkg/apache/2.2.8/modules/
cp .libs/libphp5.so /usr/local/pkg/apache/2.2.8/modules/libphp5.so
cp: cannot create regular file
`/usr/local/pkg/apache/2.2.8/modules/libphp5.so': Read-only file system
apxs:Error: Command failed with rc=65536
.
make: *** [install-sapi] Error 1


It looks like that it's trying to copy files to a place that I already know
I don't have permission on. How can I customize this step like the other one
so it's aware of where Apache actually is, and finish the installation?

Thanks,
Emily