First of all, I started out with Slackware with Linux kernel 2.2.3 on an intel box. Here's what I did to get it to compile, more or less.

1. Got the MySQL rpms from http://www.mysql.com/. (Including client, server and devel packages).
2. Used rpm2targz to convert the rpms to tar.gz files. Then, renamed them to file.tgz so that I could use pkgtool to install them.
3. Copied the tgz's to / and ran /usr/lib/setup/pkgtool to install all three of them.
4. Read the docs on MySQL and got the server running.
5. (Alternate: got the source package for MySQL on SuSe 6.1, and compiled from scratch. Then, added the line "/usr/local/lib/mysql" to /etc/ld.so.conf and ran "ldconfig" to add the library path to the MySQL libraries. If you can't find the MySQL libraries while compiling, try this, or try "export LD_LIBRARY_PATH=/usr/local/lib/mysql".)
6. Ran mysql -p to log into the MySQL server. Ran:
   create database qpopper;
   use qpopper;
   create table popUsers (username char(32), password char(32), uid mediumint(9), gid mediumint(9), maildrop char(128));
   quit;
   
   
7. Downloaded the qpopper/mysql patch from http://hades.riverstyx.net/qpopmysql/.
8. Downloaded qpopper3.0 from ftp://ftp.qualcomm.com/
9. Un-tar-gzed the qpopper package, went into the qpopper directory and did ./configure.
10. Edited mspatch as follows (I had to or it wouldn't patch.):

    [orig]
    *** -       Sun Jul 17 16:46:18 1994
    --- popper_conf.c       Thu Jan 14 21:13:14 1999
    
    [edited]
    *** ../../qpopper3.0/popper/popper_conf.c       Sun Jul 17 16:46:18 1994
    --- popper_conf.c       Thu Jan 14 21:13:14 1999
    

11. Copied mspatch into qpopper3.0/popper and ran patch -p1 < mspatch. (That's a "one" not an "ell.")
12. Edited the Makefile that came with the mspatch to change the -l[mysql library] to point to -l/usr/lib/mysql instead of -l/usr/local/mysql/lib/mysql. Also, you should probably change this to wherever your install of MySQL put your libraries. :)
13. Copied the Makefile that came with the mspatch to qpopper3.0/popper.
14. In qpopper3.0/popper/pop_init.c, commented out the case 'e': block because the sucker would not compile with it in, and I didn't feel like trying to fix it. :-)
15. Went back into qpopper3.0 directory and ran "make".
16. I basically just left everything where it was, and added the following to /etc/inetd.conf:

    pop3   stream  tcp     nowait  root    /usr/src/qpopper3.0/popper/popper popper -s
    

17. Ran a "kill -HUP" on inetd so it would re-read the inetd.conf file.
18. Created a file /etc/popper.conf with the following entries:

    MySQLUsername qpopper
    MySQLPassword password
    MySQLAuthDB qpopper
    MySQLAuthTable popUsers
    MySQLAuthUsernameField username
    MySQLAuthPasswordField password
    MySQLAuthPasswordMethod crypt
    MySQLAuthSpoolField maildrop
    

    (With different username and password, of course. :-)
19. Added a user to the mysql popUsers table.
20. Telnetted to port 110 of the host with the new qpopper, and ran:

    user username
    pass password
    

    and it worked!