Where: trunk #369.
Platform: linux/gcc (g++ (GCC) 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2))
A lot of warning coming from big_int::from_native_int due to compilation of a piece of code which isn't correct for types less or the same size as size of limb for big_int. This piece of code isn't executed for those types, but its compilation produces a lot of warnings. Should be fixed by separating that piece of code into separate function.
Since release 2.2.8 will have never been issued, moved forward to 2.2.9.
Please try HEAD revision. Should compile without this warning now.