First version of Threefish512-CTR with BLAKE3-MAC & a custom shamirs secret sharing port alongside C bridges with test vectors & Compilation instructions

crypto/shamirs_secret_sharing/include/cpython/fileutils.h

@@ -0,0 +1,8 @@
+#ifndef Py_CPYTHON_FILEUTILS_H
+#  error "this header file must not be included directly"
+#endif
+
+// Used by _testcapi which must not use the internal C API
+PyAPI_FUNC(FILE*) _Py_fopen_obj(
+    PyObject *path,
+    const char *mode);