arc: Fix build error

One part of the patch for ARC support was missing in the upstreamed
version.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Don't use 16 byte aligned stack for WIN32

This fixes a crash when accessing __stdcall functions in Python ctypes.
Merge pull request #51 from vbudovski/for_upstream

Don't use 16 byte aligned stack for WIN32
Don't align stack for win32
Merge pull request #45 from foss-for-synopsys-dwc-arc-processors/arc_support

arc: Fix build error
Merge pull request #45 from foss-for-synopsys-dwc-arc-processors/arc_support

arc: Fix build error
Merge branch 'master' of github.com:/atgreen/libffi
Fix up docs