to trigger/signal a rebuild for the transition 5.10.1 -> 5.12.1.
The list of packages is computed by finding all packages which end
up having either of PERL5_USE_PACKLIST, BUILDLINK_API_DEPENDS.perl,
or PERL5_PACKLIST defined in their make setup (tested via
"make show-vars VARNAMES=..."), minus the packages updated after
the perl package update.
sno@ was right after all, obache@ kindly asked and he@ led the
way. Thanks!
(optionally) returns an object which causes the signal handler to be reset
to the previous value, when it goes out of scope.
Also implemented is timeout_call() which takes a timeout value and a code
reference, and executes the code reference wrapped with an alarm timeout.
Finally, two convenience routines are defined which allow one to get the
signal name from the number -- sig_name(), and get the signal number from
the name -- sig_number().
