Fix reverse dependency core Updater -> library ESP8266WiFi (#6398)

* Per @earlephilhower suggestion

* Hints from @earlephilhower

* Namespace BearSSL in core "feels" wrong - using catch-all esp8266 instead.

* After review remarks by @earlephilhower

Author: dok-net

cores/esp8266/Updater.cpp

@@ -1,5 +1,4 @@
 #include "Updater.h"
-#include "Arduino.h"
 #include "eboot_command.h"
 #include <esp8266_peri.h>
 
@@ -11,10 +10,10 @@
 #endif
 
 #if ARDUINO_SIGNING
-  #include "../../libraries/ESP8266WiFi/src/BearSSLHelpers.h"
-  static BearSSL::PublicKey signPubKey(signing_pubkey);
-  static BearSSL::HashSHA256 hash;
-  static BearSSL::SigningVerifier sign(&signPubKey);
+namespace esp8266 {
+  extern UpdaterHashClass& updaterSigningHash;
+  extern UpdaterVerifyClass& updaterSigningVerifier;
+}
 #endif
 
 extern "C" {
@@ -39,7 +38,7 @@ UpdaterClass::UpdaterClass()
 , _progress_callback(nullptr)
 {
 #if ARDUINO_SIGNING
-  installSignature(&hash, &sign);
+  installSignature(&esp8266::updaterSigningHash, &esp8266::updaterSigningVerifier);
 #endif
 }
 

libraries/ESP8266WiFi/src/BearSSLHelpers.cpp

@@ -20,6 +20,7 @@
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
+#include "BearSSLHelpers.h"
 #include <memory>
 #include <vector>
 #include <bearssl/bearssl.h>
@@ -28,7 +29,10 @@
 #include <string.h>
 #include <Arduino.h>
 #include <StackThunk.h>
-#include "BearSSLHelpers.h"
+#include <Updater_Signing.h>
+#ifndef ARDUINO_SIGNING
+  #define ARDUINO_SIGNING 0
+#endif
 
 namespace brssl {
   // Code here is pulled from brssl sources, with the copyright and license
@@ -901,3 +905,17 @@ make_stack_thunk(br_ssl_engine_sendrec_buf);
 #endif
 
 };
+
+#if ARDUINO_SIGNING
+namespace {
+  static BearSSL::PublicKey signingPubKey(signing_pubkey);
+  static BearSSL::HashSHA256 __signingHash;
+  static BearSSL::SigningVerifier __signingVerifier(&signingPubKey);
+};
+
+namespace esp8266 {
+  UpdaterHashClass& updaterSigningHash = __signingHash;
+  UpdaterVerifyClass& updaterSigningVerifier = __signingVerifier;
+};
+#endif
+

libraries/ESP8266WiFi/src/BearSSLHelpers.h

@@ -26,7 +26,6 @@
 #include <bearssl/bearssl.h>
 #include <Updater.h>
 
-
 // Internal opaque structures, not needed by user applications
 namespace brssl {
   class public_key;