build.sh fails to run from the source tar.gz because the script contains ^M characters that were probably inserted by some DOS editor.
Running sed 's/^M$//' build.sh > build_unix.sh fixes the issue.
# in bash/tcsh, press Ctrl-V then Ctrl-M
Version 2.2.4 of WarGus was downloaded.
Updated importance as it makes it unusable on Linux without the script fix.