message: Fix inaccurate comment
diff: @@ -1010,8 +1010,8 @@ pub unsafe extern "C" fn unsetenv(key: *const c_char) -> c_int {
  #[no_mangle]
  pub unsafe extern "C" fn valloc(size: size_t) -> *mut c_void {
  - /* _SC_PAGESIZE is a c_long and may in principle not convert
  - * correctly to a size_t. */
  + /* sysconf(_SC_PAGESIZE) is a c_long and may in principle not
  + * convert correctly to a size_t. */
  match size_t::try_from(sysconf(_SC_PAGESIZE)) {
  Ok(page_size) => {
  /* valloc() is not supposed to be able to set errno to
  