nano: Update to version 6.3

nano: Update to version 6.3

- Update from version 6.2 to 6.3
- Update of rootfile not required
- Changelog
   Changes between v6.2 and v6.3:
    Benno Schulenberg (41):
      build: add the --disable-maintainer-mode option to ./configure
      build: fix compilation for --enable-{tiny,nanorc,color}
      build: fix compilation when configured with --disable-color
      build: remove an obsolete check -- the dependent code was deleted
      bump version numbers and add a news item for the 6.3 release
      display: suppress spotlight yellow and error red when NO_COLOR is set
      docs: add an example binding for copying text to the system clipboard
      execute: clear an anchor only when the whole buffer gets filtered
      execute: don't crash when an empty buffer is piped through a command
      execute: stay on the same line number when filtering the whole buffer
      feedback: show extra warning when writing failed due to "No space left"
      files: do not change to a higher directory when the working one is gone
      files: show a warning when the working directory is gone (when used)
      files: when the working directory exists, still check its accessibility
      filtering: close all output descriptors, so that 'xsel' will terminate
      formatting: change cursor position only after saving it in the undo item
      gnulib: pull in the workaround for a build problem on NetBSD
      gnulib: update to its current upstream state
      justify: stay at the same line number when doing a full justification
      painting: colorize text also after an unterminated start match
      painting: look for another start match only after the actual end match
      painting: recalculate the multidata when making large strides or changes
      painting: stop coloring an extremely long line after 2000 bytes
      painting: tighten the check for a lacking end match on a colored line
      syntax: xml: colorize /> properly, and colorize prolog tags differently
      syntax: xml: colorize user-defined entities differently
      tweaks: avoid a function call when two plain assignments will do
      tweaks: change the indentation of a list, to match other indentations
      tweaks: don't leave an orphaned temporary file behind when writing fails
      tweaks: elide an unneeded call of strlen()
      tweaks: exclude the extra truncation warning from the tiny version
      tweaks: make the triggering of the recalculation of multidata less eager
      tweaks: move the saving and restoring of flags to where it is needed
      tweaks: normalize the indentation after the previous change
      tweaks: prevent the adding of an unwanted newline in a different way
      tweaks: remove redundant braces, and add two translator hints
      tweaks: remove some stray spaces before a comma
      tweaks: simplify a bit of code, eliding two labels and three gotos
      tweaks: simplify a fragment of code, and fold two lines together
      tweaks: trim a few comments, rename a function, and reshuffle some code
      verbatim: with --zero, keep cursor in viewport when it was on bottom row
    Mike Frysinger (1):
      general: fix building for Windows

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>