softfloat in the kernel

[krytarowski]

I ported the berkeley-softfloat-3 library to run in the NetBSD kernel.

The only difference is that we need to include different headers than the userspace ones.

I intend to merge this into the NetBSD distribution, but would you accept the patch to make berkeley-softloat-3 buildable in such environment out of the box upstream?

Another approach would be to rely on GCC/Clang defines and redefine all the *int* types from the builtin types, such as __INT_FAST64_TYPE__. It would make berkeley-softfloat-3 fully standalone.

I prefer to avoid downstream patches if possible.