Fix top-pointer help (potentially not lock free without the fix).

3 jobs from master in 4 minutes 37 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #6445
build_cmake

01:07

 
  Test
passed #6446
run_tests

01:07

 
  Sanitizer
passed #6447
run_address_sanitizer

02:21