Fix garage_db build on 32-bit systems

src/db/lmdb_adapter.rs

@@ -327,3 +327,17 @@ where
 		}
 	}
 }
+
+// ----
+
+#[cfg(target_pointer_width = "64")]
+pub fn recommended_map_size() -> usize {
+	1usize << 40
+}
+
+#[cfg(target_pointer_width = "32")]
+pub fn recommended_map_size() -> usize {
+	use log::warn;
+	warn!("LMDB is not recommended on 32-bit systems, database size will be limited");
+	1usize << 30
+}