GNUstep Objective-C Runtime
The GNUstep Objective-C runtime is designed as a drop-in replacement for the
GCC runtime. It supports both a legacy and a modern ABI, allowing code
compiled with old versions of GCC to be supported without requiring
recompilation. The modern ABI adds the following features:
- Non-fragile instance variables.
- Protocol uniquing.
- Object planes support.
- Declared property introspection.