The e_antic spkg doesn't build with XCode 16 on macOS Sequoia

[Marc Culler]

This was the only other problem package besides gfortran.  The issue seems to be that one of the e_antic files includes a boost header which triggers a warning about assigning out-of-range values to an enum.  That warning was promoted to an error in clang 16.  Boost actually already has a workaround,, because other compilers generate errors for this as well.  So that workaround just needs to be activated for clang 16.  There is a patch in this macports ticket that does this.

- Marc