GNU Smalltalk version 2.95h (the latest release candidate) didn’t compile out-of-the-box on Mac OS X 10.3.9 for me. The two changes that were required were:

• change the header file includes in socketx.h to the older way of getting the prototypes for select(2)
• change part of a .section declaration in darwin_closure.S to remove mention of the live_support section attribute.

After these changes, gst compiles and runs well for me on my OS X 10.3.9 box.

The patch against gst 2.95h is here.