Since we have a DSL for specifying syscalls, we can create a verificaton
method for each syscall that can cover most argument (and eventually
capability) verification instead of doing it piecemeal in each syscall
implementation, which can be more error-prone.
Now a new _syscall_verify_* function exists for every syscall, which
calls the real implementation. The syscall table for the syscall handler
now maps to these verify functions.
Other changes:
- Updated the definition grammar to allow options to have a "key:value"
style, to eventually support capabilities.
- Added an "optional" option for parameters that says a syscall will
accept a null value.
- Some bonnibel fixes, as definition file changes weren't always
properly causing updates in the build dep graph.
- The syscall implementation function signatures are no longer exposed
in syscall.h. Also, the unused syscall enum has been removed.
e0246df26b