Can I do a "debug build" of GNU Smalltalk?
Debug information is usually included in the build. However, usually the resulting optimized binary is very hard to debug. So you can compile without optimization by configuring with ./configure CFLAGS=-g (or otherwise passing CFLAGS=-g to make).
You can also add the --enable-checking option to configure, which adds extra assertions at the cost of performance.
After starting gdb and before starting the VM, you have to type handle SIGSEGV noprint to ignore signals generated by the generational GC machinery.