Add Examples readme

examples/README.md

@@ -0,0 +1,30 @@
+# Examples
+
+To run the examples:
+```
+xargo rustc --target nvptx64-nvidia-cuda --release
+```
+
+## Deep Dependencies Example: `deep-deps-example`
+This example shows that the linker is actually "linking" :)
+
+The dependencies hierarchy is:
+```
+example (is the CUDA kernel dylib crate)
+└─ dummy_math (rlib crate)
+   └─ dummy_utils (rlib crate)
+```
+
+Both `dummy_math` and `dummy_utils` exports a function and also a kernel.
+
+A PTX output at `target/nvptx64-nvidia-cuda/release/example.ptx` should contain no `.extern` function declaration and have 3 kernels.
+
+
+## Undefined Reference Example: `undefined-ref-example`
+This example shows that the linker can find unresoved external references and reject linking because the output won't be a valid PTX.
+
+When you try to run the example the linker should fail with error message:
+```
+[ERROR] Unable to link modules
+[ERROR]   caused by: Undefined references: ["bar"]
+```