gh-106320: Remove private _PyTraceback functions (#108453)

Move private functions to the internal C API (pycore_traceback.h):

* _Py_DisplaySourceLine()
* _PyTraceback_Add()

Author: vstinner

Include/cpython/traceback.h

@@ -11,6 +11,3 @@ struct _traceback {
     int tb_lasti;
     int tb_lineno;
 };
-
-PyAPI_FUNC(int) _Py_DisplaySourceLine(PyObject *, PyObject *, int, int, int *, PyObject **);
-PyAPI_FUNC(void) _PyTraceback_Add(const char *, const char *, int);

Include/internal/pycore_traceback.h

@@ -8,6 +8,12 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+// Export for '_ctypes' shared extension
+PyAPI_FUNC(int) _Py_DisplaySourceLine(PyObject *, PyObject *, int, int, int *, PyObject **);
+
+// Export for 'pyexact' shared extension
+PyAPI_FUNC(void) _PyTraceback_Add(const char *, const char *, int);
+
 /* Write the Python traceback into the file 'fd'. For example:
 
        Traceback (most recent call first):

Modules/_ctypes/callproc.c

@@ -101,8 +101,10 @@ module _ctypes
 #define DONT_USE_SEH
 #endif
 
-#include "pycore_runtime.h"         // _PyRuntime
-#include "pycore_global_objects.h"  // _Py_ID()
+#include "pycore_runtime.h"       // _PyRuntime
+#include "pycore_global_objects.h"// _Py_ID()
+#include "pycore_traceback.h"     // _PyTraceback_Add()
+
 #include "clinic/callproc.c.h"
 
 #define CTYPES_CAPSULE_NAME_PYMEM "_ctypes pymem"

Modules/pyexpat.c

@@ -5,6 +5,7 @@
 #include "Python.h"
 #include "pycore_import.h"        // _PyImport_SetModule()
 #include "pycore_pyhash.h"        // _Py_HashSecret
+#include "pycore_traceback.h"     // _PyTraceback_Add()
 
 #include <ctype.h>
 #include <stddef.h>               // offsetof()

Python/_warnings.c

@@ -1,13 +1,12 @@
 #include "Python.h"
 #include "pycore_dict.h"          // _PyDict_GetItemWithError()
-#include "pycore_frame.h"
-#include "pycore_initconfig.h"
 #include "pycore_interp.h"        // PyInterpreterState.warnings
 #include "pycore_long.h"          // _PyLong_GetZero()
-#include "pycore_pyerrors.h"
+#include "pycore_pyerrors.h"      // _PyErr_Occurred()
 #include "pycore_pylifecycle.h"   // _Py_IsInterpreterFinalizing()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_sysmodule.h"     // _PySys_GetAttr()
+#include "pycore_traceback.h"     // _Py_DisplaySourceLine()
 
 #include "clinic/_warnings.c.h"