save and restore errno in the heartbeat signal handler.
save and restore errno in the heartbeat signal handler.


git-svn-id: http://squeakvm.org/svn/squeak/branches/Cog@2347 fa1542d4-bde8-0310-ad64-8ed1123d492a

Former-commit-id: c75c593a3e33a70bb0c19519d616c650200bd7fe
peteruhnak/pharo-vm,OpenSmalltalk/vm,timfel/squeakvm,bencoman/pharo-vm,peteruhnak/pharo-vm,OpenSmalltalk/vm,peteruhnak/pharo-vm,bencoman/pharo-vm,timfel/squeakvm,OpenSmalltalk/vm,bencoman/pharo-vm,bencoman/pharo-vm,peteruhnak/pharo-vm,OpenSmalltalk/vm,peteruhnak/pharo-vm,bencoman/pharo-vm,OpenSmalltalk/vm,timfel/squeakvm,peteruhnak/pharo-vm,OpenSmalltalk/vm,bencoman/pharo-vm,bencoman/pharo-vm,bencoman/pharo-vm,timfel/squeakvm,timfel/squeakvm,OpenSmalltalk/vm,timfel/squeakvm,timfel/squeakvm,timfel/squeakvm,peteruhnak/pharo-vm,peteruhnak/pharo-vm,bencoman/pharo-vm,OpenSmalltalk/vm