Update the following skaware ports:

    * devel/skalibs 2.14.3.0
    * lang/execline 2.9.6.1
    * sysutils/s6   2.13.1.0
    * s6-rc         0.5.5.0

As well as probably patch sysutils/runwhen.

More details from the release notes:

 * skalibs-2.14.3.0
   ----------------

 - Important bugfixes for some of the software stack.
 - New function: fork_newpid(), forking a process in a new pid
namespace on Linux (and returning -1 ENOSYS on other systems).
 - QoL: IOPAUSE_EXCEPT will now always trigger IOPAUSE_READ or
IOPAUSE_WRITE as well, which means error handling before the IO
primitive is now unnecessary.

 https://skarnet.org/software/skalibs/
 git://git.skarnet.org/skalibs


 * s6-2.13.1.0
   -----------

 - Some of the bugfixes are pretty impactful, and it is recommended
to upgrade (including the skalibs upgrade). You don't need to
restart your services or supervision trees if you haven't noticed
anything wrong.
 - s6-supervise now supports a new file in the service directory:
flag-newpidns. If this file is present at service spawning time,
the process will be started in a new PID namespace. (Linux only;
on other systems, the service will fail to start if the file exists.)

 https://skarnet.org/software/s6/
 git://git.skarnet.org/s6


 * s6-rc-0.5.5.0
   -------------

 - This is a minor update because a bugfix required adding a new
public API, s6rc_livedir_canon(). Apart from that, the change is
purely bugfixes.
 - You do not need to recompile your service databases.

 https://skarnet.org/software/s6-rc/
 git://git.skarnet.org/s6-rc