clean up build artifacts

README.md

@@ -3,9 +3,10 @@
 Prototype error-tolerant Brolang compiler written in Odin.
 
 ```sh
-odin build . -out:brolang
-./brolang examples/programs/prototype -o /tmp/prototype
-/tmp/prototype
+mkdir -p build
+odin build . -out:build/brolang
+./build/brolang examples/programs/prototype -o build/prototype
+./build/prototype
 ```
 
 Bodyless `c func` declarations bind exact external symbols and require concrete
@@ -19,7 +20,7 @@ Additional native inputs and libraries are passed to the final `zig cc`
 invocation in command-line order:
 
 ```sh
-./brolang examples/interop/manual -o /tmp/manual \
+./build/brolang examples/interop/manual -o build/manual \
   --link examples/interop/manual/native.c
 ```