This fixes https://savannah.gnu.org/bugs/?48125.

(The fix is slightly wasteful; speeding things up will follow later.)

Use knowledge of UTF-8 instead of converting to wide characters first.

Any control character is represented by a ^ plus an ASCII character.

Instead of showing the upper control codes like this:

   ^À ^Á ^Â ^Ã ^Ä ^Å ^Æ ^Ç ^È ^É ^Ê ^Ë ^Ì ^Í ^Î ^Ï
   ^Ð ^Ñ ^Ò ^Ó ^Ô ^Õ ^Ö ^× ^Ø ^Ù ^Ú ^Û ^Ü ^Ý ^Þ ^ß

show them like this:

   ^` ^a ^b ^c ^d ^e ^f ^g ^h ^i ^j ^k ^l ^m ^n ^o
   ^p ^q ^r ^s ^t ^u ^v ^w ^x ^y ^z ^{ ^| ^} ^~ ^=

The lower control codes continue to be shown like this:

   ^@ ^A ^B ^C ^D ^E ^F ^G ^H ^I ^J ^K ^L ^M ^N ^O
   ^P ^Q ^R ^S ^T ^U ^V ^W ^X ^Y ^Z ^[ ^\ ^] ^^ ^_

The representation of DEL (0x7F) continues as ^?.

Further, use knowledge of UTF-8 to avoid a roundtrip through
wide characters.

This fixes the second part of https://savannah.gnu.org/bugs/?48331

.
Reported-by: Mike Frysinger <vapier@gentoo.org>

This fixes the first part of https://savannah.gnu.org/bugs/?48331

.
Reported-by: Mike Frysinger <vapier@gentoo.org>

This fixes https://savannah.gnu.org/bugs/?47962 reported by Cody Taylor.

By removing from their main loops a condition that occurs just once.

Do the casting from integer to character rightaway in the first
intermediate buffer.

Just like when reading a file fails.  It needs the user's attention.

This fixes https://savannah.gnu.org/bugs/?48286

.
Reviewed-by: Benno Schulenberg <bensberg@justemail.net>
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>

Keystrokes are single integers (aided by the flags meta_key and
func_key) but in the input stream they can be encoded as escape
sequences (a series of bytes).  Characters are values in byte
range, but in UTF-8 one character can consist of multiple bytes.

Also rename two variables, because the secondary input buffer
that they refer to contains only characters (mostly just one),
never any shortcuts; and there are too many "kbinput" already.

Typing a Unicode code is always finished after at most six characters:
either retval == uni or retval == kbinput, but it can't be ERR.

The negatives are taken to mean: from the end of the file,
and: from the end of the line.

This fulfills https://savannah.gnu.org/bugs/?48248.

Also, other messages that are about --operatingdir don't use the term
"confined" either.
Suggested-by: Mario Blättermann <mario.blaettermann@gmail.com>

Switch to https and drop the www. prefix for all occurrences of the
website URL.

This fixes https://savannah.gnu.org/bugs/?48282.

This fixes https://savannah.gnu.org/bugs/?48283.

Don't make it the responsibility of the executed functions to restore
the list of shortcuts of the edit window.  Just detect whether another
menu was displayed, and if so, redisplay the main menu.

This fixes https://savannah.gnu.org/bugs/?48246.

To add a character, one does not need to allocate twice its size.
And the amount to be moved does not depend on the size of the new
character; it just needs to include the terminating zero.

(This fixes in do_output() the same logical mistakes that were fixed
in do_statusbar_output() last February, in acf19bde and 7c0e4333.)

Because when undoing a paste at the end of the buffer, the tail line
probably does not exist any more.

This fixes https://savannah.gnu.org/bugs/?48222.

(It would have been the proper fix for
https://savannah.gnu.org/bugs/?44488.)

Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

This fixes https://savannah.gnu.org/bugs/?48007

.
Tested-by: Rishabh Dave <rishabhddave@gmail.com>
Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

Specifying an operating directory should either lead to a successfull
confinement, or nano should fail to start.

(Also: save the terminal settings as soon as possible, so that an early
die() will not restore uninitialized values.)

This fixes the first part of https://savannah.gnu.org/bugs/?47798 properly.

This fixes https://savannah.gnu.org/bugs/?48103.

(The fix is wasteful -- it should only discard the multidata if actually
the name *did* change, *and* if the applicable syntax changed.)

The mark has already been unset by do_cut_text().  And any assignment
to 'mark_begin' is useless when 'mark_set' is FALSE.

This fixes https://savannah.gnu.org/bugs/?48108,
and fixes https://savannah.gnu.org/bugs/?48157.