Avoid referencing undefined ABIs on 64-bit Windows builds 64-bit Windows does not have FFI_STDCALL, FFI_THISCALL, or FFI_FASTCALL.
diff --git a/src/x86/ffi.c b/src/x86/ffi.c
index a02a8a1..e1f2447 100644
--- a/src/x86/ffi.c
+++ b/src/x86/ffi.c
@@ -318,7 +318,9 @@ ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
#endif
#ifndef X86_WIN32
+#ifndef X86_WIN64
if (cif->abi != FFI_STDCALL && cif->abi != FFI_THISCALL && cif->abi != FFI_FASTCALL)
+#endif
cif->bytes = (cif->bytes + 15) & ~0xF;
#endif