gh-106320: Remove private PyLong C API functions (#108429)

Remove private PyLong C API functions:

* _PyLong_AsByteArray()
* _PyLong_DivmodNear()
* _PyLong_Format()
* _PyLong_Frexp()
* _PyLong_FromByteArray()
* _PyLong_FromBytes()
* _PyLong_GCD()
* _PyLong_Lshift()
* _PyLong_Rshift()

Move these functions to the internal C API. No longer export
_PyLong_FromBytes() function.

Include/internal/pycore_long.h

@@ -79,9 +79,87 @@ static inline PyObject* _PyLong_FromUnsignedChar(unsigned char i)
     return (PyObject *)&_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS+i];
 }
 
-extern PyObject *_PyLong_Add(PyLongObject *left, PyLongObject *right);
-extern PyObject *_PyLong_Multiply(PyLongObject *left, PyLongObject *right);
-extern PyObject *_PyLong_Subtract(PyLongObject *left, PyLongObject *right);
+// _PyLong_Frexp returns a double x and an exponent e such that the
+// true value is approximately equal to x * 2**e.  e is >= 0.  x is
+// 0.0 if and only if the input is 0 (in which case, e and x are both
+// zeroes); otherwise, 0.5 <= abs(x) < 1.0.  On overflow, which is
+// possible if the number of bits doesn't fit into a Py_ssize_t, sets
+// OverflowError and returns -1.0 for x, 0 for e.
+//
+// Export for 'math' shared extension
+PyAPI_DATA(double) _PyLong_Frexp(PyLongObject *a, Py_ssize_t *e);
+
+extern PyObject* _PyLong_FromBytes(const char *, Py_ssize_t, int);
+
+// _PyLong_DivmodNear.  Given integers a and b, compute the nearest
+// integer q to the exact quotient a / b, rounding to the nearest even integer
+// in the case of a tie.  Return (q, r), where r = a - q*b.  The remainder r
+// will satisfy abs(r) <= abs(b)/2, with equality possible only if q is
+// even.
+//
+// Export for '_datetime' shared extension.
+PyAPI_DATA(PyObject*) _PyLong_DivmodNear(PyObject *, PyObject *);
+
+// _PyLong_FromByteArray:  View the n unsigned bytes as a binary integer in
+// base 256, and return a Python int with the same numeric value.
+// If n is 0, the integer is 0.  Else:
+// If little_endian is 1/true, bytes[n-1] is the MSB and bytes[0] the LSB;
+// else (little_endian is 0/false) bytes[0] is the MSB and bytes[n-1] the
+// LSB.
+// If is_signed is 0/false, view the bytes as a non-negative integer.
+// If is_signed is 1/true, view the bytes as a 2's-complement integer,
+// non-negative if bit 0x80 of the MSB is clear, negative if set.
+// Error returns:
+// + Return NULL with the appropriate exception set if there's not
+//   enough memory to create the Python int.
+//
+// Export for '_multibytecodec' shared extension.
+PyAPI_DATA(PyObject*) _PyLong_FromByteArray(
+    const unsigned char* bytes, size_t n,
+    int little_endian, int is_signed);
+
+// _PyLong_AsByteArray: Convert the least-significant 8*n bits of long
+// v to a base-256 integer, stored in array bytes.  Normally return 0,
+// return -1 on error.
+// If little_endian is 1/true, store the MSB at bytes[n-1] and the LSB at
+// bytes[0]; else (little_endian is 0/false) store the MSB at bytes[0] and
+// the LSB at bytes[n-1].
+// If is_signed is 0/false, it's an error if v < 0; else (v >= 0) n bytes
+// are filled and there's nothing special about bit 0x80 of the MSB.
+// If is_signed is 1/true, bytes is filled with the 2's-complement
+// representation of v's value.  Bit 0x80 of the MSB is the sign bit.
+// Error returns (-1):
+// + is_signed is 0 and v < 0.  TypeError is set in this case, and bytes
+//   isn't altered.
+// + n isn't big enough to hold the full mathematical value of v.  For
+//   example, if is_signed is 0 and there are more digits in the v than
+//   fit in n; or if is_signed is 1, v < 0, and n is just 1 bit shy of
+//   being large enough to hold a sign bit.  OverflowError is set in this
+//   case, but bytes holds the least-significant n bytes of the true value.
+//
+// Export for '_struct' shared extension.
+PyAPI_DATA(int) _PyLong_AsByteArray(PyLongObject* v,
+    unsigned char* bytes, size_t n,
+    int little_endian, int is_signed);
+
+// _PyLong_Format: Convert the long to a string object with given base,
+// appending a base prefix of 0[box] if base is 2, 8 or 16.
+// Export for '_tkinter' shared extension.
+PyAPI_DATA(PyObject*) _PyLong_Format(PyObject *obj, int base);
+
+// For use by the math.gcd() function.
+// Export for 'math' shared extension.
+PyAPI_DATA(PyObject*) _PyLong_GCD(PyObject *, PyObject *);
+
+// Export for 'math' shared extension
+PyAPI_DATA(PyObject*) _PyLong_Rshift(PyObject *, size_t);
+
+// Export for 'math' shared extension
+PyAPI_DATA(PyObject*) _PyLong_Lshift(PyObject *, size_t);
+
+extern PyObject* _PyLong_Add(PyLongObject *left, PyLongObject *right);
+extern PyObject* _PyLong_Multiply(PyLongObject *left, PyLongObject *right);
+extern PyObject* _PyLong_Subtract(PyLongObject *left, PyLongObject *right);
 
 // Export for 'binascii' shared extension.
 PyAPI_DATA(unsigned char) _PyLong_DigitValue[256];