On Windows, ctypes does no longer check the stack before and after
calling a foreign function.  This allows to use the unmodified libffi
library.

Remove most files from _ctypes/libffi_msvc, only two include files
stay (updated from _ctypes/libffi/...).  Other files are used in the
cross-platform _ctypes/libffi directory.
diff --git a/Misc/NEWS b/Misc/NEWS
index acbbc27..38fae31 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -159,6 +159,10 @@
 
 - Build the ossaudio extension on GNU/kFreeBSD.
 
+- On Windows, ctypes does no longer check the stack before and after
+  calling a foreign function.  This allows to use the unmodified
+  libffi library.
+
 Tests
 -----