Windows: Fixed build by adding a stub for `strsignal`.
Windows: Fixed build by adding a stub for `strsignal`.

Review: https://reviews.apache.org/r/52315/

andschwa/mesos,andschwa/mesos,zmalik/mesos,verizonlabs/mesos,neilconway/mesos,Gilbert88/mesos,reneploetz/mesos,abudnik/mesos,reneploetz/mesos,asamerh4/mesos,craimbert/mesos,kaysoky/mesos,Aman-Jain-14/customizedMesos,asamerh4/mesos,craimbert/mesos,gsantovena/mesos,yuquanshan/customizedMesos,craimbert/mesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,jpeach/mesos,abudnik/mesos,dforsyth/mesos,jpeach/mesos,zmalik/mesos,asamerh4/mesos,craimbert/mesos,verizonlabs/mesos,chhsia0/mesos,neilconway/mesos,craimbert/mesos,gsantovena/mesos,abudnik/mesos,gsantovena/mesos,dforsyth/mesos,dforsyth/mesos,andschwa/mesos,gsantovena/mesos,kaysoky/mesos,reneploetz/mesos,yuquanshan/customizedMesos,neilconway/mesos,Gilbert88/mesos,jpeach/mesos,chhsia0/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,reneploetz/mesos,asamerh4/mesos,gsantovena/mesos,dforsyth/mesos,kaysoky/mesos,kaysoky/mesos,yuquanshan/customizedMesos,asamerh4/mesos,asamerh4/mesos,abudnik/mesos,gsantovena/mesos,Aman-Jain-14/customizedMesos,zmalik/mesos,Gilbert88/mesos,craimbert/mesos,neilconway/mesos,andschwa/mesos,jpeach/mesos,abudnik/mesos,verizonlabs/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,dforsyth/mesos,chhsia0/mesos,Gilbert88/mesos,chhsia0/mesos,abudnik/mesos,dforsyth/mesos,yuquanshan/customizedMesos,chhsia0/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,neilconway/mesos,kaysoky/mesos,reneploetz/mesos,abudnik/mesos,craimbert/mesos,chhsia0/mesos,verizonlabs/mesos,andschwa/mesos,yuquanshan/customizedMesos,zmalik/mesos,dforsyth/mesos,reneploetz/mesos,asamerh4/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,verizonlabs/mesos,kaysoky/mesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,Gilbert88/mesos,gsantovena/mesos,jpeach/mesos,zmalik/mesos,verizonlabs/mesos,zmalik/mesos,neilconway/mesos,jpeach/mesos,yuquanshan/customizedMesos,Gilbert88/mesos,neilconway/mesos,zmalik/mesos,andschwa/mesos,andschwa/mesos