Without them, nano still compiles for me, with everything enabled,
even when using --enable-debug, --enable-utf8, and --with-slang.

The precalculation of the multiline regexes no longer looks at the
keyboard every second, and the backup code makes use of futimens()
nowadays.

Dereferencing a NULL pointer is never a good idea.

This fixes https://savannah.gnu.org/bugs/?51405

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

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.

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.

Reflect the significant changes in painting and regex searching
in the copyright notices.

The inversion of the logic in commit a6605dce was incomplete -- oops.

This fixes https://savannah.gnu.org/bugs/?50306.

When replacements are made, nothing needs to be reset any more
(it was done insufficiently anyway).  Just make sure the screen
is refreshed when all is done -- this may be superfluous when
doing interactive replacements, but not when replacing all.

The lines that come after an unpaired start have to know about this.

This fixes https://savannah.gnu.org/bugs/?50293.

When painting a line, the multidata of the line /before/ it is valid
in most cases: it was determined just a moment ago.  And it tells us
all we need to know: whether there is an unpaired start match before
the current line or not.

The only exception is when painting the first line of the screen:
the multidata of the line before it might be stale.  So for the
first screen line we will always have to do some backtracking.
But that is left for later.

This fixes https://savannah.gnu.org/bugs/?50121.

There is no need to compute the line length: just avoid overstepping
the terminating NUL byte when being forced to advance the index.

Just assign the 'CNONE' value upfront, instead of figuring out
at the end of the line whether anything has been assigned yet.

Also, the old logic would leave unmarked a line that contains a
start match without any terminating end match.  Not serious, but
not right.

Don't blithely overshoot the end of a line when both start regex and
end regex match an empty string.  Overshooting would let the matching
run on into uncharted country and thus ultimately cause a segfault.

This fixes https://savannah.gnu.org/bugs/?50056

.
Reported-by: Elia Geretto <elia.f.geretto@gmail.com>

Mentioning "GNU nano" instead of "This program" and referring to the
website instead of to a postal address.

Also, compose the coloring attributes during initialization
instead of every time when painting something.
Signed-off-by: Rishabh Dave <rishabhddave@gmail.com>
Signed-off-by: Benno Schulenberg <bensberg@justemail.net>

This fixes https://savannah.gnu.org/bugs/?48389.

Color-pair numbers and attributes can be OR'd together -- do so,
to save an attron() call whenever the hilite is on.

Precalculation of the multiline color data can be cut short when the
user is impatient and starts typing.  But this would drop the first
byte of whatever was typed -- not nice when it was just plain text,
but surprising and worse when the first keystroke was a command.

This fixes https://savannah.gnu.org/bugs/?48388.

When for a multiline syntax-coloring rule the starting regex matches at
the exact same spot as the ending regex, do a second round of resets, so
that reevaluation starts further back and gets a few more things right.

This mildly fixes https://savannah.gnu.org/bugs/?47420.

Some platforms don't like that.

If during startup there are multiple error messages, currently only the
last one remains and can be read.  To improve on that, introduce a short
pause between error messages -- even if it's not enough to read them all,
at least the user will be aware that there are multiple ones.

This also causes a few error messages to beep that currently don't beep,
such as when a file is unwritable.