hydra-evaluator: Don't use the "timeout" command

"timeout" does not propagate PR_SET_PDEATHSIG, so it prevents
hydra-eval-jobset from being killed when hydra-evaluator quits.

src/hydra-evaluator/hydra-evaluator.cc

@@ -27,8 +27,6 @@ struct Evaluator
 
     typedef std::map<JobsetName, Jobset> Jobsets;
 
-    int evalTimeout = 3600;
-
     size_t maxEvals = 4;
 
     struct State
@@ -87,7 +85,7 @@ struct Evaluator
         assert(jobset.pid == -1);
 
         jobset.pid = startProcess([&]() {
-            Strings args = { "timeout", "-s", "KILL", std::to_string(evalTimeout), "hydra-eval-jobset", jobset.name.first, jobset.name.second };
+            Strings args = { "hydra-eval-jobset", jobset.name.first, jobset.name.second };
             execvp(args.front().c_str(), stringsToCharPtrs(args).data());
             throw SysError(format("executing ‘%1%’") % args.front());
         });

src/script/hydra-eval-jobset

@@ -31,6 +31,8 @@ my $plugins = [Hydra::Plugin->instantiate(db => $db, config => $config)];
 
 my $dryRun = defined $ENV{'HYDRA_DRY_RUN'};
 
+alarm 3600; # FIXME: make configurable
+
 
 sub parseJobName {
     # Parse a job specification of the form `<project>:<jobset>:<job>