cc65: creating an Apple2 ProDOS system program?

Hi!  I've been working on a memory enhancement for the Apple2enh target for cc65, and the emulator went directly into the monitor.  :(  It seems to have extra data in the beginning of the file.  I assume this data is not supposed to be there.  Earlier today, I tried to write a program to test how cc65 handles text for the Apple2 series and got the same results.  I must be doing something wrong.  I checked the cc65 docs. and tried to remove the header.  Same result.  How do I compile a cc65 program for the Apple2?