1) Where do you get the libphp5.a?
2) Did you do 'make install' ?
3) Do you have the mysql shared libs installed?
4) And the devel packages? 
5) What does this output:
# /usr/local/mysql/bin/mysql_config --libs

1) libphp5.a appears in the libs directory alongside the libphp5.la file

2) I have tried it with both 'make' and 'make install', in this particular instance I simply used 'make' for both tests, with a 'make clean' inbetween.  First test produces the .so second test doesn't, I have tried this several times and I have even tried it by extracting from the .tar file each time 

3) mysql shared libs reside in /usr/local/mysql/lib/

4) devel packages? do you mean the headers? in /usr/local/mysql/include/

5) -L/usr/local/mysql/lib -lmysqlclient -lz -lcrypt -lnsl -lm -lc -lnss_files -lnss_dns -lresolv -lc -lnss_files -lnss_dns -lresolv

I've done it without args as well just incase that helps...

#  /usr/local/mysql/bin/mysql_config       
Usage: /usr/local/mysql/bin/mysql_config [OPTIONS]
Options:
        --cflags         [-I/usr/local/mysql/include -mcpu=pentiumpro]
        --include        [-I/usr/local/mysql/include]
        --libs           [-L/usr/local/mysql/lib -lmysqlclient -lz -lcrypt -lnsl -lm -lc -lnss_files -lnss_dns -lresolv -lc -lnss_files -lnss_dns -lresolv]
        --libs_r         [-L/usr/local/mysql/lib -lmysqlclient_r -lz -lpthread -lcrypt -lnsl -lm -lpthread -lc -lnss_files -lnss_dns -lresolv -lc -lnss_files -lnss_dns -lresolv]
        --socket         [/tmp/mysql.sock]
        --port           [3306]
        --version        [5.0.10-beta]
        --libmysqld-libs [-L/usr/local/mysql/lib -lmysqld -lpthread -lcrypt -lnsl -lm -lpthread -lc -lnss_files -lnss_dns -lresolv -lc -lnss_files -lnss_dns -lresolv -lrt]

Just tried it against the latest mysql5 binary (mysql-max-5.0.12-beta-linux-i686) and got the same result.

Can you please try with Mysql 4.1.x ? And send me the Makefile you have when the build fails to sniper@php.net

Tried against mysql4 binary (mysql-max-4.1.14-pc-linux-gnu-i686) and resulting Makefile sent via email.

Can you try the non-max mysql package instead?

In what OS are you compiling..?
You are using the PHP 5.1 snashot???

Debian GNU Linux 2.6.8-2-386

and I'm using the 5.1 snap from this morning

And what MPM is Apache2 using???

MPM is prefork model

Why don't you have gawk installed? Please install it..
Another thing to try: Compile Apache2 yourself! The CFLAGS debian build has used are really weird considering you're using prefork MPM.

Another thing going wrong is the host detection. What does this output (run in the source directory):

# sh config.guess

Another thing: exactly WHAT Debian is it?

Installed gawk, didn't make any difference.

# sh config.guess
# i686-pc-linux-gnu

Not sure I understand the question regarding what debian it is?... it's a debian install from debian.org?

Will build Apache2 from source and see if that helps.

I meant what Debian version you have. (they have names like Potato, etc..)
Please send me the config.log from the failing build.

Debian version is 'sarge'

config log sent via email.

I don't think this is any bug in PHP, it's just your Debian installation that is really messed up. Can you reproduce this on any other machine??

I don't see how my install could be messed up, I've only every used apt-get to install packages, this is the first time I've needed to build anything.

Having said that I seem to have solved it this morning, --enable-static seems to have done the trick.

Thanks for taking the time to look into this.

Let's close this for now. If someone else can actually reproduce this, I'll look again into this.