Auto-generate libc / kernel header files, as in granary1

[pgoodman]

I think it will be necessary to do something similar to what the make types and make types KERNEL=0 steps of granary1 did and auto-generate a header file that defines all macros in libc/the kernel, as well as gives type definitions for every structure. This can then be included as #include <os.h> or something, in the same way that granary clients do #include <granary.h>.

[pgoodman]

This is partially done. For user space it works, but there are issues with kernel-space compatibility.

[pgoodman]

So this was done for user space some time ago. For kernel space I hit some funny issues related to compilation.