helpztags - generate the help tags file for directory
helpztags scans given directories for *.txt and *.txt.gz
files. Each file is scanned for tags used in vim help files. For each
directory proper tags file is generated.
There should be at least one directory given. In other case
program exits with error.
Written by Jakub Turski and Artur R. Czechowski based on idea contained in
vim sources for its :helptags
Read :help helptags in vim for detailed
information about helptags.