x64 fixed, when running on arm64 Windows

x64 python, running on arm64 Windows, reports the exact same architecture
and platform as arm64 python running on arm64 Windows. We can not
distinguish between them here.

For now, neither, numpy nor CFFI support arm64 python on Windows, so we
can simply ignore it. This is ugly.

soundfile.py

@@ -158,9 +158,11 @@
     elif _sys.platform == 'win32':
         from platform import architecture as _architecture
         from platform import machine as _machine
-        if _machine() == 'ARM64':
-            _packaged_libname = 'libsndfile_arm64.dll'    
-        elif _architecture()[0] == '64bit':
+        # this check can not be completed correctly: for x64 binaries running on
+        # arm64 Windows report the same values as arm64 binaries. For now, neither
+        # numpy nor cffi are available for arm64, so we can safely assume we're
+        # in x86 land:
+        if _architecture()[0] == '64bit':
             _packaged_libname = 'libsndfile_x64.dll'
         elif _architecture()[0] == '32bit':
             _packaged_libname = 'libsndfile_x86.dll'