This reduces the namespace pollution when used in this mode.
Convert amd newvers to VARS_ONLY mode
Rather than the tedious and error-prone grep of sys/conf/newvers.sh,
use the new VARS_ONLY mode to dig out the data that's desired.
Note: I'v left the comment in newversh.sh for now. We'll revisit that
once I'm sure things have been sorted.
Convert freebsd-version to using VARS_ONLY
newvers.sh has supported a variable setting only mode, use that in
preference to grep to future proof this script from changes there.
Implement a better "VARS_ONLY" mode.
Add -v to print TYPE REVISION BRANCH RELEASE VERSION RELDATE variables
Add -V var to print var's value
Both of these in ${var}="${val}" format
Add -c to print the copyright text only.
Add -o to set VARS_ONLY=t, but this is viewed as a transient thing since
I'd like to eliminate that mode entirely.