Add Windows WSL build recommendation to temporarily disable Win32 PE support.

Author: sipsorcery

doc/build-windows.md

@@ -91,15 +91,22 @@ Note that for WSL the Bitcoin Core source path MUST be somewhere in the default
 example /usr/src/bitcoin, AND not under /mnt/d/. If this is not the case the dependency autoconf scripts will fail.
 This means you cannot use a directory that is located directly on the host Windows file system to perform the build.
 
+Additional WSL Note: WSL support for [launching Win32 applications](https://docs.microsoft.com/en-us/archive/blogs/wsl/windows-and-ubuntu-interoperability#launching-win32-applications-from-within-wsl)
+results in `Autoconf` configure scripts being able to execute Windows Portable Executable files. This can cause
+unexpected behaviour during the build, such as Win32 error dialogs for missing libraries. The recommended approach
+is to temporarily disable WSL support for Win32 applications.
+
 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" # Disable WSL support for Win32 applications.
     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
+    sudo bash -c "echo 1 > /proc/sys/fs/binfmt_misc/status" # Enable WSL support for Win32 applications.
 
 ## Depends system