In the FAQ: Build Problems, here's what it says:

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7. I can't figure out how to build PHP with Apache 1.3. 

This is actually quite easy. Follow these steps carefully: 


Grab the latest Apache 1.3 distribution from http://www.apache.org/dist/. 

Ungzip and untar it somewhere, for example /usr/local/src/apache-1.3. 

Compile PHP by first running ./configure --with-apache=/<path>/apache-1.3 (substitute <path> for the actual path to your apache-1.3 directory. 

Type 'make' followed by 'make install' to build PHP and copy the necessary files to the Apache distribution tree. 

Change directories into to your /<path>/apache-1.3/src directory and edit the Configuration file. At the end of the file, add: AddModule modules/php3/libphp3.a. 

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Well, of course, the  AddModule line should read
"libphp4.a". While this may seem obvious to the writer,
what happens is that the user thinks that might be
the name of a certain file in version 3, but that
the file name has changed in version 4. So the user
looks, and the file name is "libmodphp4.a". So he
changes it to that name, and failure occurs.

Later, there's a remark about how the writers can't
be outsmarted - to make such a remark would mean
that the writer has to be PERFECT - and that's
impossible. 

Solution: the FAQ should point out that the filename
doesn't really exist, so just change "3" to "4". If a
user slavishly followed the docs, he would just use
"3", so the writer has to help him out.

BTW, the AddModule line shouldn't be at the end - there
is another AddModule line that belongs at the end.

Suggestion: don't make comments about outsmarting the
docs writers. I can point out hundreds of errors in
the docs - users OFTEN have to read between the lines
to figure stuff out, and try to discern what the
writers really mean.

Thanx for listening....JP Harrison