wip: working on generator

- Feat: add typedefs' branches

src/compiler/generator/gen_handle.c

@@ -0,0 +1,13 @@
+#include <common/fzl_extern.h>
+#include <compiler/internals/gen.h>
+#include <stdbool.h>
+
+// Opaque pointer
+bool gen_handle(fzl_gen_t *gen, fzl_node_t *node)
+{
+  if (!gen || !node)
+    return false;
+
+  type_buf.kind = FZL_EXTERN_KIND_HANDLE;
+  return true;
+}