ugrep: updated to 4.3.4

ugrep v4.3.4

the ug command no longer quits with an error message when no default .ugrep config file was found
bzip3 is supported but not required to build ugrep; to use bzip3 with ugrep, execute ./build.sh --with-bzip3.
fix the output of + separators by no longer using them for GNU grep compatibility
fix option -v with -ABC context
fix configuration file option arguments that may got lost and causes option argument errors in some cases after parsing a config file, such as colors=
allow config file importing in config files using config=FILE (but does not permit recursive imports)
add Dockerfile-minimized
minor usability improvements

(adam)