…on-config.sh (pythonGH-3769) (python#3793)

Fix the logic in python-config.sh to avoid attempting to substitute
prefix in a variable that might have already been subject to
substitution. This e.g. happened if @exec_prefix@ was defined as
"${prefix}" (which is the default of the configure script) -- in which
case the exec_prefix_build variable was initialized with
already-subtituted prefix, and then another round of substitution was
performed which might have resulted in duplicate prefix.

To avoid that, rename the variables so that the variables matching
likely configure names (prefix, exec_prefix) retain their original
values and a '_real' suffix is used for the real values of prefix.

Furthermore, replace the unnecessary prefix and exec_prefix
substitutions with direct prefix_real references since the sed
always replaced the whole string anyway by design.
(cherry picked from commit 14086cf)

* init commit, with initial tests for from_param and fields __set__ and __get__, and some additions to from_buffer and from_buffer_copy

* added the rest of tests and patches. probably only a first draft.

* removed trailing spaces

* replace ctype with ctypes in error messages

* change back from ctypes instance to ctype instance

(cherry picked from commit 1bea762)

…completed()` (pythonGH-3830) (python#3831)

This was possible before.  pythonGH-1560 introduced a regression after 3.6.2 got
released where only sequences were accepted now.  This commit addresses this
problem.
(cherry picked from commit 574562c)

…-3842) (python#3843)

Passing a widget instead of an flist with a root widget opens the option of
creating a browser frame that is only part of a window. Passing a full file
name instead of pieces assumed to come from a .py file opens the possibility
of browsing python files that do not end in .py.
(cherry picked from commit d6bb65f)

…3848)

Save a bit of code, plus non-tuples get converted anyway to tuples by tkinter for the tk call.
(cherry picked from commit 5961e7c)

(cherry picked from commit efb560e)

…ythonGH-3699)

Use prefixed macro names for the `authoraddress` function, add T2A to the font encoding in LaTeX sources to support Cyrillic characters in the PDF documentation, and replace the deprecated `font_size` config option with `pointsize`.
(cherry picked from commit da9b4cf)

…completed()` (pythonGH-3830) (python#3831)

This was possible before.  pythonGH-1560 introduced a regression after 3.6.2 got
released where only sequences were accepted now.  This commit addresses this
problem.
(cherry picked from commit 574562c)

(cherry picked from commit efb560e)

…d split() (pythonGH-3866) (python#3874)

when pass a string larger than 2 GiB.

Decrease memory requirements for Tcl's bigmem tests.
(cherry picked from commit 27c623c)