Andrew Myers says:

It looks like when they gave options to "configure", they used single
dashes instead of the standard double dashes. E.g., "configure
-prefix=foo" instead of "configure --prefix=foo".  The double dashes
we typed in the README got turned into (Unicode) en dashes by some
tool. So our instructions had a small glitch, but we think most
developers ought to be able to recover from this -- the build notes
themselves reveal that there is some Unicode crud appearing in the
configuration command.