use std::size_t and std::ptrdiff_t in C++ code (bug #60471) Files affected: make_int.cc, file-editor-tab.cc, octave-qscintilla.cc, Cell.cc, Cell.h, call-stack.cc, call-stack.h, cellfun.cc, data.cc, debug.cc, dlmread.cc, error.cc, event-queue.h, fcn-info.cc, fcn-info.h, file-io.cc, ft-text-renderer.cc, gl2ps-print.cc, graphics.cc, graphics.in.h, help.cc, hex2num.cc, input.cc, latex-text-renderer.cc, load-path.cc, load-save.cc, load-save.h, ls-hdf5.cc, ls-mat-ascii.cc, ls-mat5.cc, ls-oct-text.cc, mex.cc, mexproto.h, mxarray.h, oct-map.cc, oct-stream.cc, oct-stream.h, pager.cc, pager.h, pr-output.cc, regexp.cc, settings.h, stack-frame.cc, stack-frame.h, strfns.cc, syminfo.cc, symrec.h, symscope.cc, symscope.h, symtab.cc, sysdep.cc, toplev.cc, utils.cc, utils.h, variables.cc, __fltk_uigetfile__.cc, __init_fltk__.cc, audioread.cc, gzip.cc, cdef-class.cc, cdef-manager.cc, cdef-method.cc, cdef-object.cc, cdef-object.h, ov-base-diag.cc, ov-base-diag.h, ov-base-mat.cc, ov-base-mat.h, ov-base-scalar.cc, ov-base-scalar.h, ov-base-sparse.h, ov-base.cc, ov-base.h, ov-cell.cc, ov-cell.h, ov-ch-mat.cc, ov-class.cc, ov-class.h, ov-classdef.cc, ov-fcn-handle.cc, ov-java.cc, ov-lazy-idx.h, ov-perm.cc, ov-perm.h, ov-range.h, ov-str-mat.cc, ov-struct.cc, ov-struct.h, ov-usr-fcn.cc, ov-usr-fcn.h, ov.cc, ov.h, ovl.cc, octave.cc, bp-table.cc, jit-ir.cc, jit-ir.h, jit-typeinfo.cc, jit-typeinfo.h, jit-util.h, lex.h, lex.ll, oct-lvalue.cc, oct-parse.yy, parse.h, profiler.h, pt-eval.cc, pt-eval.h, pt-jit.cc, pt-jit.h, pt-pr-code.cc, pt-tm-const.cc, pt-tm-const.h, Array.h, CMatrix.cc, DiagArray2.h, PermMatrix.h, Sparse.h, dMatrix.cc, fCMatrix.cc, fMatrix.cc, bsxfun-defs.cc, oct-fftw.cc, oct-fftw.h, randpoisson.cc, sparse-chol.cc, mx-inlines.cc, file-ops.cc, lo-sysdep.cc, oct-env.cc, oct-time.cc, action-container.cc, action-container.h, base-list.h, caseless-str.h, cmd-edit.cc, cmd-hist.cc, data-conv.cc, data-conv.h, f77-fcn.h, file-info.cc, file-info.h, kpse.cc, kpse.h, lo-cutils.h, lo-hash.h, lo-regexp.cc, oct-base64.cc, oct-base64.h, oct-binmap.h, oct-glob.cc, oct-shlib.cc, oct-shlib.h, oct-sort.cc, oct-sparse.h, oct-string.cc, quit.cc, unwind-prot.h, url-transfer.cc, main.in.cc, mkoctfile.in.cc, and shared-fcns.h. (grafted from aef11bb4e6d1f303ad9de5688fcb7244ef48867e)

--- a/libinterp/corefcn/data.cc	Wed Apr 28 22:23:39 2021 -0400
+++ b/libinterp/corefcn/data.cc	Wed Apr 28 22:57:42 2021 -0400
@@ -7961,7 +7961,7 @@
       if (args(0).is_ ## X ## _type ())                                  \
         {                                                                \
           const X##NDArray in = args(0).  X## _array_value ();           \
-          size_t inlen = in.numel () * sizeof (X## _t) / sizeof (char);  \
+          std::size_t inlen = in.numel () * sizeof (X## _t) / sizeof (char);  \
           const char *inc = reinterpret_cast<const char *> (in.data ()); \
           char *out;                                                     \
           if (octave::base64_encode (inc, inlen, &out))                  \
@@ -7988,7 +7988,7 @@
   else if (args(0).is_single_type ())
     {
       const Array<float> in = args(0).float_array_value ();
-      size_t inlen;
+      std::size_t inlen;
       inlen = in.numel () * sizeof (float) / sizeof (char);
       const char*  inc;
       inc = reinterpret_cast<const char *> (in.data ());
@@ -8002,7 +8002,7 @@
   else  // double_type
     {
       const Array<double> in = args(0).array_value ();
-      size_t inlen;
+      std::size_t inlen;
       inlen = in.numel () * sizeof (double) / sizeof (char);
       const char*  inc;
       inc = reinterpret_cast<const char *> (in.data ());