Build libffi from source

https://stackoverflow.com/a/40642406/323107

1. Download and install the latest version of MSYS2
   a) download the latest (64-bit or 32-bit) installer from http://msys2.github.io
   b) run the installer accepting default settings
   c) execute the following commands to update the system core
       pacman -Sy pacman
       pacman -Syu
       pacman -Su
   d) restart MSYS2, if requested to do so
   e) execute the following command to install development tools
      for 64-bit gcc:
       pacman --needed -S base-devel dejagnu mingw-w64-x86_64-gcc
      for 32-bit gcc:
       pacman --needed -S base-devel dejagnu mingw-w64-i686-gcc
   f) restart MSYS2
2. Download and compile the latest version of libffi
   a) download the latest source code bundle from https://github.com/libffi/libffi/releases
   b) unpack the source code bundle in MSYS2 tmp directory (e.g. C:\src\libffi-3.4.2)
   c) execute the following MSYS2 commands to compile libffi (adapt the version number):
       cd /c/src/libffi-3.4.2
       ./autogen.sh
       ./configure --prefix=/src/out --enable-static --disable-shared
       make
   d) copy the distributable files to the configured /c/src/out directory
       make install
      the following files are needed for the next step:
       /c/src/out/include/ffi.h
       /c/src/out/include/ffitarget.h
       /c/src/out/lib/libffi.a

Build Ffidl-0.8 from source

./configure --enable-symbols --with-tcl=/c/src/tcl8.6.11/win --prefix=/c/bin/tcl8.6.11 --exec-prefix=/c/bin/tcl8.6.11 LIBFFI_LIBS=/c/src/out/lib/libffi.a LIBFFI_CFLAGS="-IT:/c/src/out/include -DFFI_BUILDING"
make install

Win32 dll
Ffidl0.8

Although I could build it, it crashes the host application.
Don't use it.
Consider building Ffidl0.9 with MSVC.