patch vio2vo target to only rebuild outdated .vo files

2 jobs for master in 2 minutes and 6 seconds
Status Job ID Name Coverage
  Test
failed #2317
coq
iris-coq8.5.3

00:01:01

failed #2318
coq
iris-coq8.6

00:01:05

 
Name Stage Failure
failed
iris-coq8.6 Test There is an unknown failure, please try again
awk -i inplace -f awk.Makefile Makefile.coq
awk: not an option: -i
make: *** [Makefile.coq] Error 2
Makefile:28: recipe for target 'Makefile.coq' failed

real 0m0.008s
user 0m0.000s
sys 0m0.003s
ERROR: Build failed: exit code 1
failed
iris-coq8.5.3 Test There is an unknown failure, please try again
awk -i inplace -f awk.Makefile Makefile.coq
awk: not an option: -i
Makefile:28: recipe for target 'Makefile.coq' failed
make: *** [Makefile.coq] Error 2

real 0m0.008s
user 0m0.000s
sys 0m0.003s
ERROR: Build failed: exit code 1