sysutils/bottom: fix build on ARM / POWER

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:186:40
    |
186 |             const SIDL: u8 = assert_u8(libc::SIDL);
    |                              --------- ^^^^^^^^^^ expected `i8`, found `u8`
    |                              |
    |                              arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:187:40
    |
187 |             const SRUN: u8 = assert_u8(libc::SRUN);
    |                              --------- ^^^^^^^^^^ expected `i8`, found `u8`
    |                              |
    |                              arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:188:42
    |
188 |             const SSLEEP: u8 = assert_u8(libc::SSLEEP);
    |                                --------- ^^^^^^^^^^^^ expected `i8`, found `u8`
    |                                |
    |                                arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:189:41
    |
189 |             const SSTOP: u8 = assert_u8(libc::SSTOP);
    |                               --------- ^^^^^^^^^^^ expected `i8`, found `u8`
    |                               |
    |                               arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:190:41
    |
190 |             const SZOMB: u8 = assert_u8(libc::SZOMB);
    |                               --------- ^^^^^^^^^^^ expected `i8`, found `u8`
    |                               |
    |                               arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:191:41
    |
191 |             const SWAIT: u8 = assert_u8(libc::SWAIT);
    |                               --------- ^^^^^^^^^^^ expected `i8`, found `u8`
    |                               |
    |                               arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------

error[E0308]: mismatched types
   --> src/collection/processes/unix/process_ext.rs:192:41
    |
192 |             const SLOCK: u8 = assert_u8(libc::SLOCK);
    |                               --------- ^^^^^^^^^^^ expected `i8`, found `u8`
    |                               |
    |                               arguments to this function are incorrect
    |
note: function defined here
   --> src/collection/processes/unix/process_ext.rs:182:22
    |
182 |             const fn assert_u8(val: i8) -> u8 {
    |                      ^^^^^^^^^ -------