When trying to cross-compile for Windows on Ubuntu 20.04.2 LTS I ran into the following configuration error:

checking for Boost Process... configure: error: Boost::Process is required for external signer support, but not available!

Steps to reproduce:

1. depends build for windows

    cd depends && make -jN HOST=x86_64-w64-mingw32
   

2. After work is built, try to configure:

     cd .. && ./autogen.sh && CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site ./configure
   

3. Run into configuration error

System:

• reproduced on VM with Ubuntu 20.04.2 LTS and desktop with Arch Linux