Added transparent software breakpoint support for user debuggers:

* The bulk of the work -- i.e. juggling the software and hardware breakpoints,
  watchpoints, and memory reads/writes -- is done in the new class
  BreakpointManager.
* For the architectures a few capability macros have to be defined, one
  pointing to the software breakpoint instruction opcode. Done for x86.
* Some more simplifications in the user debugger code, made possible by the
  recently introduced debugger_changed_condition attribute.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@31214 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/user_debugger.h

@@ -20,6 +20,7 @@
 #define	B_DEBUG_PROFILE_BUFFER_FLUSH_THRESHOLD	70			/* in % */
 
 
+struct BreakpointManager;
 struct ConditionVariable;
 struct function_profile_info;
 struct thread;
@@ -70,6 +71,9 @@ struct team_debug_info {
 		// variable the thread won't be deleted (until unsetting it) -- it might
 		// be removed from the team hash table, though.
 
+	struct BreakpointManager* breakpoint_manager;
+		// manages hard- and software breakpoints
+
 	struct arch_team_debug_info	arch_info;
 };