Log Message:
tig: update to 2.5.4.

tig-2.5.4
---------

Improvements:

 - Add FreeBSD installation instructions. (#1093)
 - Add TIG_EDITOR environment variable to configure editor. (#889, #1098)
 - Enable mailmap by default to match git log's behaviour. (#1104, #1105)
 - Enable tilde expansion for diff-highlight. (#1107)

Bug fixes:

 - Escape variables with %% in external commands. (#1091, #1095)
 - Fix parsing of -L argument. (#1100)
 - Bugfix: smart-case does not work when search term contains a space. (#1108)
 - Use ncursesw by default on Linux. (#920)
 - Replace obsolete macro `AC_CONFIG_HEADER' in configure.ac.