Add base structure for dev compiler backend

Currently we only generate a single static function, but it is probably
loaded and run with jit. This is the base to start generating proper
code.

compiler/gen_dev/src/run_roc.rs

@@ -0,0 +1,31 @@
+#[macro_export]
+/// run_jit_function_raw runs an unwrapped jit function.
+/// The function could throw an execption and break things, or worse, it could not throw and exception and break things.
+/// This functions is generally a bad idea with an untrused backend, but is being used for now for development purposes.
+macro_rules! run_jit_function_raw {
+    ($lib: expr, $main_fn_name: expr, $ty:ty, $transform:expr) => {{
+        let v: std::vec::Vec<roc_problem::can::Problem> = std::vec::Vec::new();
+        run_jit_function_raw!($lib, $main_fn_name, $ty, $transform, v)
+    }};
+
+    ($lib: expr, $main_fn_name: expr, $ty:ty, $transform:expr, $errors:expr) => {{
+        unsafe {
+            let main: libloading::Symbol<unsafe extern "C" fn() -> $ty> = $lib
+                .get($main_fn_name.as_bytes())
+                .ok()
+                .ok_or(format!("Unable to JIT compile `{}`", $main_fn_name))
+                .expect("errored");
+
+            let result = main();
+
+            assert_eq!(
+                $errors,
+                std::vec::Vec::new(),
+                "Encountered errors: {:?}",
+                $errors
+            );
+
+            $transform(result)
+        }
+    }};
+}