Update README with info about Smalltalk bindings (#5893)

README.md

@@ -199,6 +199,11 @@ The Julia package [Z3.jl](https://github.com/ahumenberger/Z3.jl) wraps the C++ A
 
 A WebAssembly build with associated TypeScript typings is published on npm as [z3-solver](https://www.npmjs.com/package/z3-solver). Information about building these bindings can be found in [src/api/js](src/api/js).
 
+### Smalltalk (``Pharo`` / ``Smalltalk/X``)
+
+Project [MachineArithmetic](https://github.com/shingarov/MachineArithmetic) provides Smalltalk interface
+to Z3's C API. For more information, see [MachineArithmetic/README.md](https://github.com/shingarov/MachineArithmetic/blob/pure-z3/MachineArithmetic/README.md)
+
 ## System Overview
 
 ![System Diagram](https://github.com/Z3Prover/doc/blob/master/programmingz3/images/Z3Overall.jpg)
@@ -215,5 +220,6 @@ A WebAssembly build with associated TypeScript typings is published on npm as [z
 * C
 * OCaml
 * [Julia](https://github.com/ahumenberger/Z3.jl)
+* [Smalltalk](https://github.com/shingarov/MachineArithmetic/blob/pure-z3/MachineArithmetic/README.md) (supports Pharo and Smalltalk/X)