* fhandler_registry.cc (RegOpenUserClassesRoot): Only define when

building against w32api headers.
	(RegOpenCurrentUser): Ditto.
	* fhandler_tty.cc (GetNamedPipeClientProcessId): Ditto.
	* ntdll.h (enum _PROCESSINFOCLASS): Add ProcessImageFileName.
	(RtlInitAnsiString): Declare.
	(RtlUnicodeStringToAnsiSize): Declare.
	* sched.cc (GetForegroundWindow): Ditto.
	* sec_helper.cc (SECURITY_NT_NON_UNIQUE): Define as
	SECURITY_NT_NON_UNIQUE_RID when building against w32api headers.
	(cygsid::get_sid): Use SECURITY_NT_NON_UNIQUE rather than
	SECURITY_NT_NON_UNIQUE_RID.
	(__sec_user): Use PISECURITY_DESCRIPTOR rather than PSECURITY_DESCRIPTOR
	to allow valid pointer arithmetic.
	(_recycler_sd): Ditto.
	(_everyone_sd): Ditto.

winsup/cygwin/fhandler_tty.cc

@@ -1482,7 +1482,9 @@ fhandler_pty_slave::fixup_after_exec ()
     fixup_after_fork (NULL);
 }
 
+#ifndef __MINGW64_VERSION_MAJOR
 extern "C" BOOL WINAPI GetNamedPipeClientProcessId (HANDLE, PULONG);
+#endif
 
 /* This thread function handles the master control pipe.  It waits for a
    client to connect.  Then it checks if the client process has permissions