* child_info.h (CURR_CHILD_INFO_MAGIC): Reset for previous changes.

* dcrt0.cc (get_cygwin_startup_info): Signal readiness when stracing since
strace::write_child relies on it.  Use strace.activate to notify strace
process, passing in arg indicating whether we're forked.
* sigproc.cc (wait_sig): Accommodate new strace::activate argument.
* spawn.cc (child_info_spawn::worker): Oops.  Previous suspended test was
actually correct.  Revert and document.
* strace.cc (strace::activate): Send additional flag indicating whether this is
an attempt to activate a forked process.
(strace::hello): Report on windows pid.
* include/sys/strace.h (strace::strace): Make a dummy.
(strace::activate): Modify declaration to accept an argument.
(strace::write_childpid): Set regparm.

winsup/cygwin/spawn.cc

@@ -692,7 +692,8 @@ loop:
       goto out;
     }
 
-  if (iscygwin ())
+  /* The CREATE_SUSPENDED case is handled below */
+  if (!(c_flags & CREATE_SUSPENDED))
     strace.write_childpid (*this, pi.dwProcessId);
 
   /* Fixup the parent data structures if needed and resume the child's