Currently developers can't run the s_docs script if they have a doxygen version less than 1.8.17. This disallows developers to run any auto generation or validation on the existing docs e.g. spellchk, check_docs_data.

Recent changes added to the s_docs script:

v=`(echo "1.8.17" && doxygen --version) | sort -V | head -1`
test "$v" = "1.8.17" || {
	echo "$0 skipped: unsupported version of doxygen"
	exit 0
}

The idea is to investigate a fix, where we can still run the s_docs script, but not cause a failure in our build system if the doxygen version doesn't match with the system.