* 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/cygwin.h

@@ -66,7 +66,10 @@ typedef enum
     CW_INIT_EXCEPTIONS,
     CW_GET_CYGDRIVE_INFO,
     CW_SET_CYGWIN_REGISTRY_NAME,
-    CW_GET_CYGWIN_REGISTRY_NAME
+    CW_GET_CYGWIN_REGISTRY_NAME,
+    CW_STRACE_ON,
+    CW_STRACE_OFF,
+    CW_CYGWIN_PID_TO_WINPID
   } cygwin_getinfo_types;
 
 #define CW_NEXTPID	0x80000000	// or with pid to get next one
@@ -205,6 +208,11 @@ extern int cygwin_attach_handle_to_fd (char *, int, HANDLE, mode_t, DWORD);
 
 #define TTY_CONSOLE	0x40000000
 
+#ifndef _SYS_TYPES_H
+typedef short uid_t;
+typedef short gid_t;
+#endif
+
 struct external_pinfo
   {
   pid_t pid;