* exceptions.cc (signal_exit): Kill any executing child process if we're dying.

* path.h: Remove unneeded extern.
* spawn.cc (std_suffixes): Make static.  Don't set dwProcessId here since it
makes the process unsignalable.  Set strace flag that this is an execed process
stub.
* strace.cc (strace::vsprntf): Use strace flag to indicate when to visually
flag that this is an exec stub.
* include/sys/strace.h (strace): Add 'execing' flag.

winsup/cygwin/exceptions.cc

@@ -1017,6 +1017,8 @@ exit_sig:
 static void
 signal_exit (int rc)
 {
+  extern HANDLE hExeced;
+
   rc = EXIT_SIGNAL | (rc << 8);
   if (exit_already++)
     myself->exit (rc);
@@ -1035,6 +1037,9 @@ signal_exit (int rc)
   user_data->resourcelocks->Delete ();
   user_data->resourcelocks->Init ();
 
+  if (hExeced)
+    TerminateProcess (hExeced, rc);
+
   do_exit (rc);
 }