build: Add --disable-bip70 configure option

This patch adds a --disable-bip70 configure option that disables BIP70
payment request support. When disabled, this removes the dependency of
the GUI on OpenSSL and Protobuf.

src/qt/sendcoinsentry.cpp

@@ -2,6 +2,10 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
 #include <qt/sendcoinsentry.h>
 #include <qt/forms/ui_sendcoinsentry.h>
 
@@ -133,9 +137,11 @@ bool SendCoinsEntry::validate(interfaces::Node& node)
     // Check input validity
     bool retval = true;
 
+#ifdef ENABLE_BIP70
     // Skip checks for payment request
     if (recipient.paymentRequest.IsInitialized())
         return retval;
+#endif
 
     if (!model->validateAddress(ui->payTo->text()))
     {
@@ -166,9 +172,11 @@ bool SendCoinsEntry::validate(interfaces::Node& node)
 
 SendCoinsRecipient SendCoinsEntry::getValue()
 {
+#ifdef ENABLE_BIP70
     // Payment request
     if (recipient.paymentRequest.IsInitialized())
         return recipient;
+#endif
 
     // Normal payment
     recipient.address = ui->payTo->text();
@@ -196,6 +204,7 @@ void SendCoinsEntry::setValue(const SendCoinsRecipient &value)
 {
     recipient = value;
 
+#ifdef ENABLE_BIP70
     if (recipient.paymentRequest.IsInitialized()) // payment request
     {
         if (recipient.authenticatedMerchant.isEmpty()) // unauthenticated
@@ -216,6 +225,7 @@ void SendCoinsEntry::setValue(const SendCoinsRecipient &value)
         }
     }
     else // normal payment
+#endif
     {
         // message
         ui->messageTextLabel->setText(recipient.message);