Use unsafe blocks in sys/random.h implementation

src/header/sys_random/mod.rs

@@ -2,6 +2,9 @@
 //!
 //! Non-POSIX, see <https://www.man7.org/linux/man-pages/man2/getrandom.2.html>.
 
+// TODO: set this for entire crate when possible
+#![deny(unsafe_op_in_unsafe_fn)]
+
 use core::slice;
 
 use crate::{
@@ -21,7 +24,7 @@ pub const GRND_RANDOM: c_uint = 2;
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn getrandom(buf: *mut c_void, buflen: size_t, flags: c_uint) -> ssize_t {
     Sys::getrandom(
-        slice::from_raw_parts_mut(buf as *mut u8, buflen as usize),
+        unsafe { slice::from_raw_parts_mut(buf as *mut u8, buflen as usize) },
         flags,
     )
     .map(|read| read as ssize_t)