This fixes https://savannah.gnu.org/bugs/?51457.

Since all indentation and unindentation is by a tab, or by a tab's
worth of spaces, use tabsize directly.

This is the first step toward splitting them into two dedicated
functions, instead of letting do_indent() handle both cases.

When compiling with 'clang', it would say: warning: expression which
evaluates to zero treated as a null pointer constant of type 'char *'.

This avoids some warnings when compiled with -pedantic:

    ISO C forbids comparison of ‘void *’ with function pointer
    ISO C forbids empty initializer braces

In the tiny version, Ctrl+Left and Ctrl+Right are available only
in the editor itself and in the file browser.

This fixes https://savannah.gnu.org/bugs/?51173.

Achieve this by making the suppression flag global, so that we can
just reset it instead of making an improper call of do_cursorpos().

This fixes the secondary part of https://savannah.gnu.org/bugs/?51134.

It is no longer necessary to assign up() and down() separately for
the help viewer because by now the movement keys have been sorted
in order of ascending stride also in the main menu.

The two string definitions are relocated just to reduce the number
of #ifdefs.

Apparently the curses on SunOS is less forgiving than the one on GNU.
Or rather: delwin(NULL) should just return an error, it shouldn't crash.

This fixes https://savannah.gnu.org/bugs/?51053

.
Reported-by: John Wiersba <jrw32982@yahoo.com>
Solved-by: John Wiersba <jrw32982@yahoo.com>

Also, allow rebinding the word and block jumping functions
in the tiny version when nanorc files are reenabled.

(This should have been part of 9ea5eef2, four commits ago.)

Also, allow Ctrl+Left/Right with --enable-tiny --enable-browser.

Also remove a superfluous check for 'do_replace' -- it never gets
bound in the Search/Replace menus.

When configured with --enable-tiny --enable-multibuffer,
/do/ include the new-buffer toggle in the Read-File menu.

Add missing spaces, remove excess spaces, and
replace groups of indentation spaces with tabs.

And hide the cursor again as soon as the user scrolls.
Achieve this through making the 'didfind' variable global.

Also, remove a superfluous call of wnoutrefresh(), as bottombars()
already does that.

This fixes https://savannah.gnu.org/bugs/?50918

.
Reported-by: David Lawrence Ramsey <pooka109@gmail.com>

Also, trim some comments and avoid an unused-variable warning.

This avoids https://savannah.gnu.org/bugs/?49912 while at the same time
avoiding to draw the edit window twice in a row -- the first drawing
would use a wrong margin, which results in a visible and irritating
shift left or right of the content upon the second drawing.

This fixes https://savannah.gnu.org/bugs/?50877.

Backspace is a more logical counterpart of Space than minus.

It complained of "Unbound key" until now.

That is: nest the conditions consistently.
And in the bargain rename the variable.

And in the process transform the token DISABLE_HELP to ENABLE_HELP.

Allow the user to search in a help text with ^W and M-W.

Achieve this by not writing the help text directly to the screen
but first writing it to a temporary file and then opening this file
in a new buffer, and treating it specially: the normal file-reading
feedback is suppressed, the titlebar shows the headline of the text,
the cursor is hidden, and the menu is limited to just the up and down
movements and searching.

This fulfills https://savannah.gnu.org/bugs/?28994

.
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>

File formats, appending and prepending, and backups are not available
when --enable-tiny is used, so prevent all relevant pieces of code from
getting compiled.  And correct two misspelled ENABLE_TINY to NANO_TINY.

This also groups ^I and ^M together, and cutwordleft and cutwordright
(when they are bound).  It furthermore makes that less pairs are now
mixed and instead consist of either two Ctrl or two Meta combos.  In
short: it looks better in the default config.  The only sacrifice is
that Verbatim is now split off from the other "inserting" keys.

When UTF-8 is available, use actual arrows instead of untranslated words
to indicate the cursor keys in the search history, as is done elsewhere.

The interval 2013-2017 for the Free Software Foundation is valid
because in those years there were releases with changes by either
Chris or David, and the GNU maintainers guide advises to mention
a new year in all files of a package, not just in the ones that
actually changed, and be done with it for the rest of the year.

Also, M-A is far more mnemonic for setting the mark than ^6 or ^^,
so it's better to try and teach the user that.

On some terminal emulators, Ctrl+Home and Ctrl+End produce special
keycodes, distinct from plain Home and End.  Make the users of those
emulators (and of the Linux console) glad by making ^Home and ^End
do the obvious thing, and the combinations with Shift too.

When UTF-8 is available, use actual arrows instead of untranslated words
to indicate the cursor keys.  This was already done for the combinations
with Ctrl but not yet for the plain cursor keys.

The unshifted shortcuts are easier to type, and also less confusing in
my eyes.  Putting them first means they get shown in the help lines,
and get listed first in the ^G help text.

(I would also like to put ^- first instead of ^_ (because the latter
is hard to see when using the default inverse video for shortcuts),
but on several terminal emulators Ctrl+- reduces the font size.)

Making ^Up and ^Down go to top and bottom row in the file browser
complements and completes the behavior of ^Left and ^Right.

Put all the movement keys together, in order of ascending stride.

Also, move the Undo/Redo keystrokes further up, so that, when the
user has a somewhat wider terminal than the usual 80 characters,
these keystrokes will be shown -- they are far more interesting
than the ^Y and ^V ones, for which PgUp and PgDn can be used.

Since all lines can be partially scrolled off the screen now
(except for edittop, which is forthcoming), the maxlines global
variable and its computation mechanism are no longer needed.

These improvements will eventually make do_home() and do_end() take
parameters.  Since the global function lists can hold only functions
without parameters, preemptively add do_home_void() and do_end_void(),
and make the global function lists use them.