mc: update to 4.8.20.

Version 4.8.20

- Core

  * Rename key bindings:
    * [main].PanelListingSwitch -> [panel].CycleListingFormat
    * [main].PanelListingChange -> [main].SetupListingFormat
  * Speed up of UTF-8 normalization for frequent cases (#3616)

- VFS

  * extfs helpers tester:
    * diff of failed tests is now included in output to ease bug reporting (#3784)

- Editor

  * Syntax:
    * ES2015 support (#3793)
    * TypeScript support (#3794)
    * Ada 95 updates (#3804)
    * Apache Hive QL support (#3828)
    * SQL & PHP keyword updates (MidnightCommander/mc#129)
    * Simplification of case insensitive file name patterns in /usr/share/mc/syntax/Syntax file (#3829)
    * Markdown (initial support) (#3864)
    * Protocol Buffers and gRPC support (#3868)
  * Add %c (cursor offset from BOF) support for user menu macros (#3867)

- Misc

  * Unify curses initialization for various curses implementations (#3697)
  * Highlight txz extension as archive like tgz, etc. (#3782)
  * Add new media extensions to `filehighlight.ini` (#3834)

- Fixes

  * Wrong --help message for mcview, mcedit and mcdiff (#3805)
  * Compression from menu broken due to bad quoting (#3840)
  * `--with-homedir` gives "yes" as config directory (#3836)
  * External panelize: opening a file with an absolute path fails (#2942)
  * Filter isn't cleared when entering empty string (#3813)
  * Panelization is not kept while switching panel listing mode (#3810)
  * Cannot tab out of a QuickView panel (#3815)
  * Cannot use the F10 key in a QuickView panel (#3816)
  * Wromg INPUT_COMPLETE_CD flag handling in the QuickDialog engine (#3870)
  * mcview: file interpreted as latin1 instead of utf8 (#3783)
  * mcview: incomplete read of filtering data (#3817)
  * mcview: search doesn't grow file as much as needed (#3819, #3855)
  * mcview: goto doesn't grow file as much as needed (#3826)
  * mcview: quick view panel: crash on slow startup while switching panel mode (#3846)
  * mcedit: fix broken encoding into UTF-8 for 8-bit displays (#3843)
  * mcedit: incorrect %f macro substitution in the user menu (#3861)
  * man pages: wrong paths of mc.hint and mc.hlp (#3806)
  * subshell: fix broken tcsh 6.20+ cd escaping (#3852)
  * VFS: incremental tar doesn't contain empty directories (#2297)
  * VFS: incremental tar: wrong directories owner for tar --numeric-owner -g (#3709)
  * VFS: timestamps not being preserved due to uninitialized struct stat st_[acm]tim.tv_nsec (#3821)
  * VFS: ftp: can't retrieve password from .netrc when user is in URL (#3869)
  * VFS: tests: locale issue causing helpers using 'sort' to fail (#3787)
  * VFS: tests: unportable 'echo' use causing one rpm helper test to fail (#3786)
  * Spelling errors in the manual page (#3839)

(wiz)