-/* Given a block, find the name of the block's crate. The name must
- be freed by the caller. Returns NULL if no crate name can be
- found. */
-extern char *rust_crate_for_block (const struct block *block);
+/* Given a block, find the name of the block's crate. Returns an empty
+ stringif no crate name can be found. */
+extern std::string rust_crate_for_block (const struct block *block);