gh-37064: Fix build when linbox is build with fplll support
Undefine flint macros that conflict with fplll variables and break build
when both are included
See https://github.com/sagemath/sage/pull/36449#issuecomment-1891095354
URL: https://github.com/sagemath/sage/pull/37064
Reported by: Antonio Rojas
Reviewer(s): Tobias Diez, Vincent Delecroix