os: update os namespace for 15.0.0, loader/ro: update to use csrng, spl: bump max sessions

libraries/libstratosphere/include/stratosphere/os/os_interrupt_event_api.hpp

@@ -17,6 +17,7 @@
 #pragma once
 #include <vapours.hpp>
 #include <stratosphere/os/os_interrupt_event_common.hpp>
+#include <stratosphere/os/os_native_handle.hpp>
 
 namespace ams::os {
 
@@ -31,6 +32,8 @@ namespace ams::os {
     bool TimedWaitInterruptEvent(InterruptEventType *event, TimeSpan timeout);
     void ClearInterruptEvent(InterruptEventType *event);
 
+    NativeHandle GetInterruptEventHandle(const InterruptEventType *event);
+
     void InitializeMultiWaitHolder(MultiWaitHolderType *multi_wait_holder, InterruptEventType *event);
 
 }