The "libffi" directory holds a copy of libffi version 3.1.
The libffi code is distributed under an LGPL-compatible license.

Our copy of libffi for Racket has been changed in a few small:

 * Test ftruncate() result in "closures.c" to avoid a compiler
   warning.

 * In "x86/darwin.S", added ".long 0" after ".LFE3:" to avoid
   problems compiling with gcc-4.0.

 * In "x86/win32.S", added ".long 0" after ".LFE5:" and ".LEFDE5", and
   also included `.section .eh_frame,"w"` for X86_DARWIN --- again,
   all to avoid problems compiling with gcc-4.0.