prettify treiber stack

2 jobs for master
Status Job ID Name Coverage
  Build
failed #22397
fp-timing
build-coq.8.8.2

00:05:24

canceled #22395
fp-timing
build-coq.8.8.2

 
Name Stage Failure
failed
build-coq.8.8.2 Build
Makefile.coq:317: recipe for target 'all' failed
make[1]: *** [all] Error 2
Makefile:6: recipe for target 'all' failed
make: *** [all] Error 2

real 4m26.106s
user 18m19.240s
sys 0m30.328s
ERROR: Job failed: exit code 1