gitian: add a gitian-win-signer descriptor

This is exactly like the current OSX signing process.

osslsigncode has been patched to detach and re-attach Windows signatures.
The changes can be seen here: https://github.com/theuni/osslsigncode/commits/attach-signature

There's a pull-request open upstream for the changes:
https://sourceforge.net/p/osslsigncode/osslsigncode/merge-requests/3/

This work has been back-ported to the stable 1.7.1 release of osslsigncode, so
that a smaller patch can be reviewed.

contrib/gitian-descriptors/gitian-win-signer.yml

@@ -0,0 +1,34 @@
+---
+name: "bitcoin-win-signer"
+suites:
+- "precise"
+architectures:
+- "amd64"
+packages:
+- "libssl-dev"
+- "autoconf"
+reference_datetime: "2015-06-01 00:00:00"
+remotes:
+- "url": "https://github.com/bitcoin/bitcoin-detached-sigs.git"
+  "dir": "signature"
+files:
+- "osslsigncode-1.7.1.tar.gz"
+- "osslsigncode-Backports-to-1.7.1.patch"
+- "bitcoin-win32-setup.exe"
+- "bitcoin-win64-setup.exe"
+script: |
+  BUILD_DIR=`pwd`
+  SIGDIR=${BUILD_DIR}/signature/win
+
+  echo "f9a8cdb38b9c309326764ebc937cba1523a3a751a7ab05df3ecc99d18ae466c9  osslsigncode-1.7.1.tar.gz" | sha256sum -c
+  echo "a8c4e9cafba922f89de0df1f2152e7be286aba73f78505169bc351a7938dd911  osslsigncode-Backports-to-1.7.1.patch" | sha256sum -c
+
+  tar xf osslsigncode-1.7.1.tar.gz
+  cd osslsigncode-1.7.1
+  patch -p1 < ${BUILD_DIR}/osslsigncode-Backports-to-1.7.1.patch
+
+  ./configure --without-gsf --without-curl --disable-dependency-tracking
+  make
+
+  ./osslsigncode attach-signature -in ${BUILD_DIR}/bitcoin-win32-setup.exe -out ${OUTDIR}/bitcoin-win32-setup-signed.exe -sigin ${SIGDIR}/bitcoin-win32-setup.exe.pem
+  ./osslsigncode attach-signature -in ${BUILD_DIR}/bitcoin-win64-setup.exe -out ${OUTDIR}/bitcoin-win64-setup-signed.exe -sigin ${SIGDIR}/bitcoin-win64-setup.exe.pem

doc/release-process.md

@@ -41,6 +41,8 @@ Release Process
 ###fetch and build inputs: (first time, or when dependency versions change)
  
 	mkdir -p inputs
+	wget -P inputs https://bitcoincore.org/cfields/osslsigncode-Backports-to-1.7.1.patch
+	wget -P inputs http://downloads.sourceforge.net/project/osslsigncode/osslsigncode/osslsigncode-1.7.1.tar.gz
 
  Register and download the Apple SDK: (see OSX Readme for details)
  
@@ -65,7 +67,9 @@ Release Process
 	mv build/out/bitcoin-*.tar.gz build/out/src/bitcoin-*.tar.gz ../
 	./bin/gbuild --commit bitcoin=v${VERSION} ../bitcoin/contrib/gitian-descriptors/gitian-win.yml
 	./bin/gsign --signer $SIGNER --release ${VERSION}-win --destination ../gitian.sigs/ ../bitcoin/contrib/gitian-descriptors/gitian-win.yml
-	mv build/out/bitcoin-*.zip build/out/bitcoin-*.exe ../
+	mv build/out/bitcoin-*.zip ../
+	mv build/out/bitcoin-*-win64-setup.exe inputs/bitcoin-win64-setup.exe
+	mv build/out/bitcoin-*-win32-setup.exe inputs/bitcoin-win32-setup.exe
 	./bin/gbuild --commit bitcoin=v${VERSION} ../bitcoin/contrib/gitian-descriptors/gitian-osx.yml
 	./bin/gsign --signer $SIGNER --release ${VERSION}-osx-unsigned --destination ../gitian.sigs/ ../bitcoin/contrib/gitian-descriptors/gitian-osx.yml
 	mv build/out/bitcoin-*-unsigned.tar.gz inputs/bitcoin-osx-unsigned.tar.gz
@@ -75,7 +79,7 @@ Release Process
 
   1. source tarball (bitcoin-${VERSION}.tar.gz)
   2. linux 32-bit and 64-bit binaries dist tarballs (bitcoin-${VERSION}-linux[32|64].tar.gz)
-  3. windows 32-bit and 64-bit installers and dist zips (bitcoin-${VERSION}-win[32|64]-setup.exe, bitcoin-${VERSION}-win[32|64].zip)
+  3. windows 32-bit and 64-bit unsigned installers and dist zips (bitcoin-${VERSION}-win[32|64]-setup.exe, bitcoin-${VERSION}-win[32|64].zip)
   4. OSX unsigned installer (bitcoin-${VERSION}-osx-unsigned.dmg)
   5. Gitian signatures (in gitian.sigs/${VERSION}-<linux|win|osx-unsigned>/(your gitian key)/
 
@@ -91,9 +95,9 @@ Commit your signature to gitian.sigs:
 	git push  # Assuming you can push to the gitian.sigs tree
 	popd
 
-  Wait for OSX detached signature:
-	Once the OSX build has 3 matching signatures, it will be signed with the Apple App-Store key.
-	A detached signature will then be committed to the bitcoin-detached-sigs repository, which can be combined with the unsigned app to create a signed binary.
+  Wait for Windows/OSX detached signatures:
+	Once the Windows/OSX builds each have 3 matching signatures, they will be signed with their respective release keys.
+	Detached signatures will then be committed to the bitcoin-detached-sigs repository, which can be combined with the unsigned apps to create signed binaries.
 
   Create the signed OSX binary:
 
@@ -103,10 +107,20 @@ Commit your signature to gitian.sigs:
 	mv build/out/bitcoin-osx-signed.dmg ../bitcoin-${VERSION}-osx.dmg
 	popd
 
-Commit your signature for the signed OSX binary:
+  Create the signed Windows binaries:
+
+	pushd ./gitian-builder
+	./bin/gbuild -i --commit signature=v${VERSION} ../bitcoin/contrib/gitian-descriptors/gitian-win-signer.yml
+	./bin/gsign --signer $SIGNER --release ${VERSION}-win-signed --destination ../gitian.sigs/ ../bitcoin/contrib/gitian-descriptors/gitian-win-signer.yml
+	mv build/out/bitcoin-win64-setup-signed.exe ../bitcoin-${VERSION}-win64-setup.exe
+	mv build/out/bitcoin-win32-setup-signed.exe ../bitcoin-${VERSION}-win32-setup.exe
+	popd
+
+Commit your signature for the signed OSX/Windows binaries:
 
 	pushd gitian.sigs
 	git add ${VERSION}-osx-signed/${SIGNER}
+	git add ${VERSION}-win-signed/${SIGNER}
 	git commit -a
 	git push  # Assuming you can push to the gitian.sigs tree
 	popd
@@ -115,12 +129,6 @@ Commit your signature for the signed OSX binary:
 
 ### After 3 or more people have gitian-built and their results match:
 
-- Perform code-signing.
-
-    - Code-sign Windows -setup.exe (in a Windows virtual machine using signtool)
-
-  Note: only Gavin has the code-signing keys currently.
-
 - Create `SHA256SUMS.asc` for the builds, and GPG-sign it:
 ```bash
 sha256sum * > SHA256SUMS