$(datarootdir) should be $(datadir)

[Jack T Mudge III]

In section 7.2.5, when the 'datadir' directory is discussed, this
sentence appears:

"This should normally be /usr/local/share, but write it as
$(datarootdir). (If you are using Autoconf, write it as '@datadir@')"

$(datarootdir) should be $(datadir), given the section it's in.

Hope it helps!