Instead be more specific and say that the directory is not writable.

This addresses https://bugs.debian.org/831636 reported by Christoph Biedl.

This fixes https://savannah.gnu.org/bugs/?47296.

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

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.

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.)

This fixes https://savannah.gnu.org/bugs/?48156.

Don't catch the NULL earlier, because we do want an error message when
opening the lockfile fails.

That is: don't mix the number of lines read with a warning about the
file being unwritable -- the former is just convenience information,
the latter is a must-see.

This fixes https://savannah.gnu.org/bugs/?48047.

And to contrast it more with 'answer'.

When calling do_prompt(), 'ans' is used to offer a default answer or the
answer given so far.

The relative path could be . or .. or even empty, which is uninformative.

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

Move the initialization of the operating directory to after the
initialization of the screen, so that the above error can be shown.

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

Between the first stat (that sets 'realexists') and the second stat
(directly after), the file might have disappeared, which would mean
that current_stat would be NULL.  Prevent dereferencing this further
down.

Only when the user decides not to override an existing lockfile should
loading the corresponding file be skipped.  Any failure to write the
lockfile should be ignored -- the file itself should be loaded anyway.

This fixes https://savannah.gnu.org/bugs/?47945.

Error messages about lock files should not get overwritten by purely
informational messages, only by alerting ones.

This fixes https://savannah.gnu.org/bugs/?47963.

The variable 'namecopy' has been passed to dirname(), so it is likely
to have been changed when it contains a slash.  So, use a new variable
instead.  Also, free the result of display_string().

This fixes https://savannah.gnu.org/bugs/?47956.

Having just opened a fresh buffer, 'openfile->next' will never be NULL,
because the list is circular.

Second, when compiled with --disable-nultibuffer, and deciding not to
override an existing lock, the 'return FALSE' should *not* be skipped,
because otherwise the named file will be opened after all.

This fixes an unreported bug.

Make the failures to read or write a lock file into important messages,
so they will not be overwritten by the number of lines read.

The general mechanism for not allowing important messages to be overwritten
will take care of not overwriting warnings about failed file lockings.