[patch] port libffi to x86/msvc

[Timothy Wall]

On Jan 13, 2010, at 6:40 PM, Dan Witte wrote:

>
> Patch descriptions are below. The first patch consolidates the stack  
> space allocation code; it's currently fragmented between  
> ffi_prep_cif and ffi_prep_cif_machdep depending on X86, X86_DARWIN,  
> or X86_WIN64, which made it somewhat hard to read. The second merges  
> ffi_call_SYSV and ffi_call_STDCALL since they're identical. The  
> third fixes a few MSVC syntax errors and adds the assembly routines.

I haven't looked at the patch yet, but ffi_call_SYSV and  
ffi_call_STDCALL are not identical, since stdcall must pop its own  
args from the stack.  I think I originally wrote it to share code  
between two functions, with only a little bit on the ends for stdcall,  
but someone added some debug/stack metadata that required the two  
functions be distinct, thus the duplicated code.