Redirect stdout/stderr to android logcat

Underlying wallet error messages were not going anywhere useful; this
redirects them into the android logger so that you can access them (e.g.
with adb logcat).

lib/routes.dart

@@ -32,7 +32,7 @@ class Routes {
   static const addressBookAddContact = '/address_book_add_contact';
   static const dangerzoneKeys = '/dangerzone/keys';
   static const dangerzoneSeed = '/dangerzone/seed';
-  static const dangerzoneRemoveWallet = '//dangerzone/remove_wallet';
+  static const dangerzoneRemoveWallet = '/dangerzone/remove_wallet';
   static const showKeys = '/dangerzone/show/keys';
   static const subaddressList = '/subaddress_list';
   static const restoreWalletFromSeedDetails = '/restore_from_seed_details';

lib/src/wallet/oxen/oxen_wallet.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:collection/collection.dart';
 import 'package:hive/hive.dart';
 import 'package:oxen_coin/stake.dart' as oxen_stake;
 import 'package:oxen_coin/transaction_history.dart' as transaction_history;
@@ -55,7 +56,20 @@ class OxenWallet extends Wallet {
   static Future<OxenWallet> load(
       Box<WalletInfo> walletInfoSource, String name, WalletType type) async {
     final id = (walletTypeToString(type)?.toLowerCase() ?? 'unknown') + '_' + name;
-    final walletInfo = walletInfoSource.values.firstWhere((info) => info.id == id);
+    print('Loading wallet $id');
+
+    var walletInfo = walletInfoSource.values.firstWhereOrNull((info) => info.id == id);
+    if (walletInfo == null) {
+        walletInfo = WalletInfo(
+            id: id,
+            name: name,
+            type: type,
+            timestamp: DateTime.now().millisecondsSinceEpoch,
+            // We don't know what these were, so use conservative values:
+            isRecovery: false,
+            restoreHeight: 0);
+        walletInfoSource.add(walletInfo);
+    }
     return await configured(
         walletInfoSource: walletInfoSource, walletInfo: walletInfo);
   }

lib/src/wallet/oxen/oxen_wallets_manager.dart

@@ -121,7 +121,7 @@ class OxenWalletsManager extends WalletsManager {
 
   @override
   Future<Wallet> openWallet(String name, String password) async {
-    print('opening a Wallet with nettype $nettype');
+    print('opening Wallet $name with nettype $nettype');
     try {
       final path = await pathForWallet(name: name);
       oxen_wallet_manager.openWallet(path: path, password: password, nettype: nettype);

lib/src/wallet/wallets_manager.dart

@@ -15,4 +15,4 @@ abstract class WalletsManager {
   Future<bool> isWalletExit(String name);
 
   Future remove(WalletDescription wallet);
-}
+}

oxen_coin/android/CMakeLists.txt

@@ -21,5 +21,5 @@ set_target_properties(wallet_api PROPERTIES IMPORTED_LOCATION
 
 include_directories( ${EXTERNAL_LIBS_DIR}/oxen/include )
 
-target_link_libraries( oxen_coin PRIVATE wallet_api )
+target_link_libraries( oxen_coin PRIVATE wallet_api log )
 target_include_directories( oxen_coin PRIVATE wallet_api )

oxen_coin/ios/Classes/oxen_api.cpp

@@ -6,6 +6,7 @@
 #include <iostream>
 #include <unistd.h>
 #include <thread>
+#include <mutex>
 // #include "OxenWalletListener.h"
 #ifdef ANDROID
 #include "../External/android/oxen/include/wallet2_api.h"
@@ -18,6 +19,37 @@ namespace Oxen = Wallet;
 // Macro to force symbol visibility, and prevent the symbol being stripped
 #define EXPORT __attribute__((visibility("default"))) __attribute__((used))
 
+
+#ifdef __ANDROID_API__
+extern "C" int __android_log_write(int prio, const char* tag, const char* text);
+static bool start_logger()
+{
+    // Set stdout/stderr to the typical line-buffered and unbuffered:
+    setvbuf(stdout, 0, _IOLBF, 0);
+    setvbuf(stderr, 0, _IONBF, 0);
+
+    // Create a pipe and redirect both stdout/stderr into it:
+    int pipe_fd[2];
+    pipe(pipe_fd);
+    dup2(pipe_fd[1], 1);
+    dup2(pipe_fd[1], 2);
+
+    // Spawn and detach a logging thread that forever captures stderr (via the pipe) and redirects
+    // it into the android log subsystem:
+    std::thread{[](int fd) {
+        ssize_t sz;
+        char buf[4096];
+        while ((sz = read(fd, buf, sizeof(buf) - 1)) > 0) {
+            if (buf[sz - 1] == '\n') --sz; // strip trailing newline (android_log_write adds one)
+            buf[sz] = 0; // null terminate
+            __android_log_write(4 /*ANDROID_LOG_INFO*/, "oxen-wallet", buf);
+        }
+    }, pipe_fd[0]}.detach();
+    return true;
+}
+static bool started_logger = start_logger();
+#endif
+
 extern "C"
 {
     typedef struct