libxl: fork: Provide LIBXL_HAVE_SIGCHLD_SELECTIVE_REAP
This is the feature test macro for libxl_childproc_sigchld_occurred
and libxl_sigchld_owner_libxl_always_selective_reap.
It is split out into this separate patch because: a single feature
test is sensible because we do not intend anyone to release or ship
libxl versions with one of these but not the other; but, the two
features are in separate patches for clarity; and, this just makes
reading the actual code easier.
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Jim Fehlig <jfehlig@suse.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>