freebsd-dev/contrib/ntp/sntp/loc
..
darwin
debian
freebsd
legacy
netbsd
README
redhat
solaris

If you look at the files here you should be able to figure out what is
being done.

../scripts/genLocInfo handles the parsing of these files.

If no "more specific" file has been found and cvo.sh says the OS is
redhat* or fedora*, we will look for loc/redhat .

If no "mode specific" file has been found and the "uname" command returns
"Linux", we will look for loc/linux .

Note that automake has interesting behavior - we build the man pages using
the man_MANS target, but they are actually installed using the empty
manX_MANS= target, which "does the right thing".  This means that we
need to have empty manX_MANS= targets for each possible X, based on
the data in the loc/ files.  For executables, this generally means
sections 1 and 8.