Where is ecos.mak?

I rebuilt the library, and I think I found my problem: last time, the mouse pointer changed back to a regular pointer after I chose "Build -> Library", so I thought it was done and exited the program. The text pane at the bottom of the window wasn't showing any activity (apparently you have to scroll it down to the bottom for that), I didn't look at the status line, there were no animations or anything saying it was busy, and it didn't ask me if I wanted to abort the build in progress when I chose "File -> Exit". Now, after rebuilding, it is there, and a lot more than just the header files. Thanks!