* exceptions.cc (unused_sig_wrapper): Eliminate unused parameter to asm.

* external.cc (cygwin_internal): Change CW_STRACE_ON to CW_STRACE_TOGGLE.
* strace.cc (strace::hello): Toggle strace on and off.
* sync.cc (muto::init): Renamed from constructor.
* sync.h (muto::new): Delete.
(muto::delete): Ditto.
(new_muto): Simplify.  Use muto.init for nearly everything.
* uinfo.cc (uinfo_init): Avoid closing a NULL handle.
* include/sys/cygwin.h (cygwin_getinfo_types): Rename CW_STRACE_OFF to
CW_STRACE_TOGGLE.  Delete CW_STRACE_OFF.
* include/sys/strace.h (strace): Add "inited" field.

winsup/cygwin/strace.cc

@@ -34,6 +34,13 @@ void
 strace::hello()
 {
   char buf[30];
+
+  if (inited)
+    {
+      active ^= 1;
+      return;
+    }
+
   __small_sprintf (buf, "cYg%8x %x", _STRACE_INTERFACE_ACTIVATE_ADDR, &active);
   OutputDebugString (buf);