* external.cc (cygwin_internal): Initialize various internal settings if

required to allow use of some things from user loaded DLL.
(CW_STRACE_ON): Add new feature.
(CW_CYGWIN_PID_TO_WINPID): Ditto.
* pinfo.cc (set_myself): Call "strace.hello" to initiate possible strace
session.
(pinfo::init): Guard against dereferencing uninitialized myself.
* sigproc.cc (wait_sig): Call strace.hello() when __SIGTRACE "signal" received.
* strace.cc (strace::hello): New method.
* wincap.cc (wincapc::init): Avoid initializing if already initialized.
* wincap.h (wincapc::wincapc): New method.
* include/sys/cygwin.h: Add new CW_ enums.  Kludge typedefs of {g,u}id_t if
required.
* strace.h (strace::hello): Declare new method.

winsup/cygwin/include/sys/strace.h

@@ -44,6 +44,7 @@ public:
   int lmicrosec;
   int execing;
   strace() : version(1) {}
+  void hello ();
   void prntf (unsigned, const char *func, const char *, ...) /*__attribute__ ((regparm(3)))*/;
   void vprntf (unsigned, const char *func, const char *, va_list ap) /*__attribute__ ((regparm(3)))*/;
   void wm (int message, int word, int lon) __attribute__ ((regparm(3)));