As Toni said, the merge is still work in progress. Most changes are not yet in WinUAE. That is also the cause for your compiler warnings and the unused headers.
In the meantime i have worked on FMOD and FREM. After some testing i think we have now a quite good SoftFloat implementation for them. Comparing it to math.h freml, remainderl and remquol shows identical results with in range numbers, even with weird inputs like 1e32 % 5. With invalid inputs remquol returns 0, same with SoftFloat. So that should be OK too.
The native implementation now gives correct remainders, but bad quotients for invalid inputs and for input values with big differences in magnitude (difference of Exponent > 63). That would be hard to fix. Another reason to keep working on SoftFloat. Anyway the new native float implementation is much better than the old one, which gave wrong remainders for numbers with big differences in magnitude and returned no quotient at all.
Now all arithmetic functions are implemented, except FSINH, FETOXM1, FTANH, FATAN, FASIN, FATANH, FETOX, FTWOTOX, FTENTOX, FCOSH and FACOS.