How to use buildtool?

[Richard Kennaway]

(Is this list dead? No postings for two years. Where else should I take this 
enquiry?)

I have a command-line tool written in C++ and built with XCode on a Mac, which 
I'm trying to port to a Linux machine.  I came across buildtool, which promises 
to interpret the Xcode project file and carry out the build using the gnustep 
tools.  I've installed gnustep, xcode, and buildtool, but it is not clear to me 
how to use buildtool. No documentation comes with it and I've found none on the 
web.

From reading the source code, it takes two arguments, the name of the Xcode 
project and a command to buildtool to tell it what to do with it.  I see 
nothing in the source to reveal what commands are available, except that the 
default is "build".  When I try that, buildtool begins by attempting to build a 
target that I don't want to build for this platform and wouldn't make any sense 
there (it's an iOS app).

How can I tell buildtool which target I want to build?  I have tried guessing 
its commands, but so far it has responded to everything with "Unknown build 
operation".

-- 
Richard Kennaway