Unable to find foreign function in rubinius

output

$ ruby -rlibusb -e ''
An exception occurred requiring command line files
    Unable to find foreign function '[:libusb_device_handle, :int]' (FFI::NotFoundError)

Backtrace:
                FFI::Library(Module)#ffi_function_missing at kernel/delta/ffi.rb:9
                     FFI::Library(Module)#attach_function at kernel/platform/library.rb:130
                      LIBUSB::Call.__module_init__ (Call) at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/gems/1.9/gems/libusb-0.2.2/lib/libusb/call.rb:192
                          LIBUSB.__module_init__ (LIBUSB) at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/gems/1.9/gems/libusb-0.2.2/lib/libusb/call.rb:21
                                        Object#__script__ at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/gems/1.9/gems/libusb-0.2.2/lib/libusb/call.rb:19
                             Rubinius::CodeLoader.require at kernel/common/codeloader.rb:212
            Kernel(Module)#gem_original_require (require) at kernel/common/kernel.rb:648
                                   Kernel(Module)#require at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/lib/rubygems/custom_require.rb:36
                          LIBUSB.__module_init__ (LIBUSB) at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/gems/1.9/gems/libusb-0.2.2/lib/libusb.rb:19
                                        Object#__script__ at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/gems/1.9/gems/libusb-0.2.2/lib/libusb.rb:16
                             Rubinius::CodeLoader.require at kernel/common/codeloader.rb:212
  Kernel(Rubinius::Loader)#gem_original_require (require) at kernel/common/kernel.rb:648
                         Kernel(Rubinius::Loader)#require at /home/renaud/.rbenv/versions/rbx-2.0.0-dev/lib/rubygems/custom_require.rb:60
                         { } in Rubinius::Loader#requires at kernel/loader.rb:568
                                               Array#each at kernel/bootstrap/array.rb:68
                                Rubinius::Loader#requires at kernel/loader.rb:568
                                    Rubinius::Loader#main at kernel/loader.rb:814

Problematic code (assumption)

typedef :pointer, :libusb_context
typedef :pointer, :libusb_device_handle

attach_function 'libusb_set_configuration', [:libusb_device_handle, :int], :int, :blocking=>true
attach_function 'libusb_claim_interface', [:libusb_device_handle, :int], :int
attach_function 'libusb_release_interface', [:libusb_device_handle, :int], :int, :blocking=>true
[…]
attach_function 'libusb_handle_events', [:libusb_context], :int, :blocking=>true

rubinius#2064_workaround.patch

diff --git a/lib/libusb/call.rb b/lib/libusb/call.rb
index e0604b7..252ee86 100644
--- a/lib/libusb/call.rb
+++ b/lib/libusb/call.rb
@@ -21,7 +21,7 @@ module LIBUSB
   module Call
     extend FFI::Library
 
-    if FFI::Platform.windows?
+    if FFI::Platform::OS == 'windows'
       bundled_dll = File.join(File.dirname(__FILE__), '..', 'libusb-1.0.dll')
       ffi_lib(['libusb-1.0', bundled_dll])
     else

rubinius2064_workaround.patch

diff --git a/lib/libusb/call.rb b/lib/libusb/call.rb
index e0604b7..252ee86 100644
--- a/lib/libusb/call.rb
+++ b/lib/libusb/call.rb
@@ -21,7 +21,7 @@ module LIBUSB
   module Call
     extend FFI::Library
 
-    if FFI::Platform.windows?
+    if FFI::Platform::OS == 'windows'
       bundled_dll = File.join(File.dirname(__FILE__), '..', 'libusb-1.0.dll')
       ffi_lib(['libusb-1.0', bundled_dll])
     else