message: doc: Install only "-posix" MinGW compiler when possible
diff: @@ -48,8 +48,17 @@ Acquire the source in the usual way:
  ## Building for 64-bit Windows
  The first step is to install the mingw-w64 cross-compilation tool chain:
  + - on modern systems (Ubuntu 21.04 Hirsute Hippo or newer, Debian 11 Bullseye or newer):
  +```sh
  +sudo apt install g++-mingw-w64-x86-64-posix
  +```
  +
  + - on older systems:
  +
  +```sh
  sudo apt install g++-mingw-w64-x86-64
  +```
  Once the toolchain is installed the build steps are common:
  