Problem: Crash syncing swapfile in new buffer when using sodium crypt.
(James McCoy)
Solution: Add checks for sodium encryption. (Christian Brabandt,
closes#12591, closes#12585)
Problem: Get E304 when using 'cryptmethod' "xchacha20v2". (Steve Mynott)
Solution: Add 4th crypt method to block zero ID check. Avoid syncing a swap
file before reading the file. (closes#12433)
Problem: Decrypting with libsodium may fail if the library changes.
Solution: Add parameters used to the encrypted file header. (Christian
Brabandt, closes#12279)
Problem: Crypt test fails on MS-Windows if xxd was not installed yet.
Solution: Use the just built xxd executable if it exists. (James McCoy,
closes#8929)
Problem: When using xchaha20 crypt undo file is not removed.
Solution: Reset 'undofile' and delete the file. (Christian Brabandt,
closes#8630, closes#8467)
Problem: Various inconsistencies in test files.
Solution: Add modelines where they were missing. Use Check commands instead
of silently skipping over tests. Adjust indents and comments.
(Ken Takata, closes#6695)
Problem: Some balloon tests don't run when they can.
Solution: Split GUI balloon tests off into a separate file. (Ozaki Kiichi,
closes#4538) Change the feature check into a command for
consistency.
