modernizing the windows xcompile process under WSL

WSL has changed some, this needs to be updated to reflect WSL1 vs 2

1 files changed, 44 insertions, 15 deletions

diff --git a/doc/build-windows.md b/doc/build-windows.md
index 9549a4b9d..4d7d6c67a 100644
--- a/doc/build-windows.md
+++ b/doc/build-windows.md
@@ -26,18 +26,15 @@ Windows](https://msdn.microsoft.com/en-us/commandline/wsl/install_guide).
 
 To get the bash shell, you must first activate the feature in Windows.
 
-1. Turn on Developer Mode
-  * Open Settings -> Update and Security -> For developers
-  * Select the Developer Mode radio button
-  * Restart if necessary
-2. Enable the Windows Subsystem for Linux feature
-  * From Start, search for "Turn Windows features on or off" (type 'turn')
-  * Select Windows Subsystem for Linux (beta)
-  * Click OK
-  * Restart if necessary
+1. Enable the Windows Subsystem for Linux feature
+  * Open the Windows Features dialog (`OptionalFeatures.exe`)
+  * Enable 'Windows Subsystem for Linux'
+  * Click 'OK' and restart if necessary
+2. Install Ubuntu
+  * Open Microsoft Store and search for "Ubuntu 18.04" or use [this link](https://www.microsoft.com/store/productId/9N9TNGVNDL3Q)
+  * Click Install
 3. Complete Installation
-  * Open a cmd prompt and type "bash"
-  * Accept the license
+  * Open a cmd prompt and type "Ubuntu1804"
   * Create a new UNIX user account (this is a separate account from your Windows account)
 
 After the bash shell is active, you can follow the instructions below, starting
@@ -53,7 +50,13 @@ installing the toolchain will be different.
 
 First, install the general dependencies:
 
-    sudo apt-get install build-essential libtool autotools-dev automake pkg-config bsdmainutils curl
+    sudo apt update
+    sudo apt upgrade
+    sudo apt-get install build-essential libtool autotools-dev automake pkg-config bsdmainutils curl git
+    
+If you want to build with the wallet and Qt GUI you also want to install the following (this example is under Ubuntu):
+
+    sudo apt-get install libssl-dev libboost-all-dev qt5-default libprotobuf-dev libqrencode4 libdb++-dev libdb-dev miniupnpc
 
 A host toolchain (`build-essential`) is necessary because some dependency
 packages (such as `protobuf`) need to build host utilities that are used in the
@@ -63,17 +66,43 @@ build process.
 
 To build executables for Windows 64-bit, install the following dependencies:
 
-    sudo apt-get install g++-mingw-w64-x86-64 mingw-w64-x86-64-dev
+    sudo apt-get install g++-mingw-w64-x86-64
 
-Then build using:
+For Ubuntu 18.04 and 20.04, set the default mingw32 g++ compiler option to posix:
+
+    sudo update-alternatives --config x86_64-w64-mingw32-g++ 
+
+...Choose the "posix" (vs 'auto' or 'win32') option, and continue.
+
+Note that for WSL v1 the Dogecoin Core source path MUST be somewhere in the default mount file system, for
+example /usr/src/dogecoin, AND not under, for example, /mnt/d/dogecoin. 
+
+If this is not the case the dependency autoconf scripts will fail (silently.)
+This means you cannot use a directory that is located directly on the host Windows file system to perform the build.
+
+If using WSL 1, you'll need to turn off WSL Support for Win32 applications temporarily, or you will get ABI errors and format errors for some .o files.
+
+If using WSL 1 then build using:
 
+    PATH=$(echo "$PATH" | sed -e 's/:\/mnt.*//g') # strip out problematic Windows %PATH% imported var
+    sudo bash -c "echo 0 > /proc/sys/fs/binfmt_misc/status" # Temporarily Disable WSL support for Win32 applications.
     cd depends
     make HOST=x86_64-w64-mingw32
     cd ..
-    ./autogen.sh # not required when building from tarball
+    ./autogen.sh
     CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site ./configure --prefix=/
     make
+    sudo bash -c "echo 1 > /proc/sys/fs/binfmt_misc/status" # Re-Enable WSL support for Win32 applications.
+    
+If using WSL 2 then you should be able to build just with:
 
+    cd depends
+    make HOST=x86_64-w64-mingw32
+    cd ..
+    ./autogen.sh # not required when building from tarball
+    CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site ./configure --prefix=/
+    make
+    
 ## Building for 32-bit Windows
 
 To build executables for Windows 32-bit, install the following dependencies: