I'd like to set up an environment for learning objective C on my laptop.
I'm using Hardy on a 32-bit system.

I found this page:

But the installation instructions were brief and insufficient.

I install these packages via apt-get:
gnustep gnustep-base-runtime gnustep-base-libgnustep-base-dev libgnustep-base1.14 libgnustep-gui-dev libgnustep-gui0.12 common

Compiling his example, I get:

hello.m:2:34: error: Foundation/Foundation.h: No such file or directory
hello.m:5: error: cannot find interface declaration for ‘NSObject’, superclass of ‘HelloWorld’
hello.m: In function ‘-[HelloWorld hello]’:
hello.m:10: error: cannot find interface declaration for ‘NXConstantString’
hello.m: In function ‘main’:
hello.m:15: warning: ‘HelloWorld’ may not respond to ‘+alloc’
hello.m:15: warning: (Messages without a matching method signature
hello.m:15: warning: will be assumed to return ‘id’ and accept
hello.m:15: warning: ‘...’ as arguments.)
hello.m:15: warning: no ‘-init’ method found
hello.m:17: warning: ‘HelloWorld’ may not respond to ‘-release’

I figure the first line means that I'm missing an essential set of header files. I'm also guessing that this should be fixed after I apt-get the right package.

Which further package or packages do I need?