Functions that use raw pointers should be unsafe

[kornelski]

Functions like these are a loophole in Rust's safety:

pub fn add_cached_mapping(name: *mut i8) -> u64 {

add_cached_mapping(12345 as *mut i8);

can cause a segfault despite being "safe".

These functions should be either marked as unsafe, or take CStr, or a &'static str or &'static [u8] and checking them for \0.