Attempt to work around macOS vfork bug

Problem reported by YAMAMOTO Mitsuharu in:
http://lists.gnu.org/archive/html/emacs-devel/2017-05/msg00342.html
This is related to the fix for Bug#26397.
* src/callproc.c (call_process_cleanup, call_process) [!MSDOS]:
Report internal error if wait_for_termination fails.
* src/sysdep.c (get_child_status): Return -1 if waitpid is
buggy, instead of aborting.
(wait_for_termination): Return bool success value.
All callers changed.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/callproc.c b/src/callproc.c
index e967e45d03f..7c85eed835f 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -202,10 +202,11 @@ call_process_cleanup (Lisp_Object buffer)
       message1 ("Waiting for process to die...(type C-g again to kill it instantly)");
 
       /* This will quit on C-g.  */
-      wait_for_termination (synch_process_pid, 0, 1);
-
+      bool wait_ok = wait_for_termination (synch_process_pid, NULL, true);
       synch_process_pid = 0;
-      message1 ("Waiting for process to die...done");
+      message1 (wait_ok
+                ? "Waiting for process to die...done"
+                : "Waiting for process to die...internal error");
     }
 #endif  /* !MSDOS */
 }
@@ -866,9 +867,10 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd,
                make_number (total_read));
     }
 
+  bool wait_ok = true;
 #ifndef MSDOS
   /* Wait for it to terminate, unless it already has.  */
-  wait_for_termination (pid, &status, fd0 < 0);
+  wait_ok = wait_for_termination (pid, &status, fd0 < 0);
 #endif
 
   /* Don't kill any children that the subprocess may have left behind
@@ -878,6 +880,9 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd,
   SAFE_FREE ();
   unbind_to (count, Qnil);
 
+  if (!wait_ok)
+    return build_unibyte_string ("internal error");
+
   if (WIFSIGNALED (status))
     {
       const char *signame;