Line 9373 of configure: elif test x$enable_cups == xyes; then gives an error with /bin/sh. All test $x == $y should be replaced with test $a = $b. man bash says: string1 == string2 True if the strings are equal. = may be used in place of == for strict POSIX compliance.
should already be fixed in 3.0 tree.
sorry for the same, cleaning up the database to prevent unecessary reopens of bugs.