* 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/include/sys/strace.h

@@ -43,6 +43,7 @@ public:
   int active;
   int lmicrosec;
   int execing;
+  int inited;
   strace() : version(1) {}
   void hello ();
   void prntf (unsigned, const char *func, const char *, ...) /*__attribute__ ((regparm(3)))*/;