Merge branch 'jk/execv-dashed-external' into maint

Typing ^C to pager, which usually does not kill it, killed Git and
took the pager down as a collateral damage in certain process-tree
structure.  This has been fixed.

* jk/execv-dashed-external:
  execv_dashed_external: wait for child on signal death
  execv_dashed_external: stop exiting with negative code
  execv_dashed_external: use child_process struct