[$] Capability analysis for the kernel

One of the advantages of the Rust type system is its ability to encapsulate
requirements about the state of the program in the type system;
often, this state includes which locks must be held to be able to carry out
specific operations. C lacks the ability to express these
requirements, but there would be obvious benefits if that kind of feature
could be grafted onto the language. The Clang compiler has made some
strides in that direction with its thread-safety
analysis feature; two developers have been independently working to
take advantage of that work for the kernel.