Define wxDEBUG_LEVEL in both debug and release builds as 1.

By default include assertions and debug logging in both debug and release
builds but disable them in application release builds (when NDEBUG is
defined).

Also update (more accurately, replace) debugging overview.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61886 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/debug.h

@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        debug.h
+// Name:        wx/debug.h
 // Purpose:     interface of global functions
 // Author:      wxWidgets team
 // RCS-ID:      $Id$
@@ -14,15 +14,35 @@
 
     Preprocessor symbol defining the level of debug support available.
 
-    Currently wxDEBUG_LEVEL is 0 in release builds (__WXDEBUG__ not defined)
-    and 1 in debug builds (it is). In the immediate future this will change
-    however and this symbol will be defined directly as 0, 1 or 2 while
-    __WXDEBUG__ won't be used by wxWidgets any longer.
+    This symbol is defined to 1 by default meaning that asserts are compiled in
+    (although they may be disabled by a call to wxDisableAsserts()). You may
+    predefine it as 0 prior to including any wxWidgets headers to omit the
+    calls to wxASSERT() and related macros entirely in your own code and you
+    may also predefine it as 0 when building wxWidgets to also avoid including
+    any asserts in wxWidgets itself.
+
+    Alternatively, you may predefine it as 2 to include wxASSERT_LEVEL_2() and
+    similar macros which are used for asserts which have non-trivial run-time
+    costs and so are disabled by default.
+
+    @since 2.9.1
 
     @header{wx/debug.h}
  */
 #define wxDEBUG_LEVEL
 
+/**
+    @def __WXDEBUG__
+
+    Compatibility macro indicating presence of debug support.
+
+    This symbol is defined if wxDEBUG_LEVEL is greater than 0 and undefined
+    otherwise.
+
+    @header{wx/debug.h}
+ */
+#define __WXDEBUG__
+
 /**
     Type for the function called in case of assert failure.
 
@@ -218,9 +238,33 @@ typedef void (*wxAssertHandler_t)(const wxString& file,
     Disable the condition checks in the assertions.
 
     This is the same as calling wxSetAssertHandler() with @NULL handler.
+
+    @since 2.9.0
+
+    @header{wx/debug.h}
  */
 void wxDisableAsserts();
 
+/**
+    @def wxDISABLE_ASSERTS_IN_RELEASE_BUILD
+
+    Use this macro to disable asserts in release build when not using
+    IMPLEMENT_APP().
+
+    By default, assert message boxes are suppressed in release build by
+    IMPLEMENT_APP() which uses this macro. If you don't use IMPLEMENT_APP()
+    because your application initializes wxWidgets directly (e.g. calls
+    wxEntry() or wxEntryStart() itself) but still want to suppress assert
+    notifications in release build you need to use this macro directly.
+
+    @see wxDISABLE_DEBUG_SUPPORT()
+
+    @since 2.9.1
+
+    @header{wx/debug.h}
+ */
+#define wxDISABLE_ASSERTS_IN_RELEASE_BUILD() wxDisableAsserts()
+
 /**
     Will always generate an assert error if this code is reached (in debug mode).
     Note that you don't have to (and cannot) use brackets when invoking this
@@ -298,10 +342,26 @@ bool wxIsDebuggerRunning();
         The previous assert handler which is not @NULL by default but could be
         @NULL if it had been previously set to this value using this function.
 
+    @since 2.9.0
+
     @header{wx/debug.h}
  */
 wxAssertHandler_t wxSetAssertHandler(wxAssertHandler_t handler);
 
+/**
+    Reset the assert handler to default function which shows a message box when
+    an assert happens.
+
+    This can be useful for the applications compiled in release build (with @c
+    NDEBUG defined) for which the asserts are by default disabled: if you wish
+    to enable them even in this case you need to call this function.
+
+    @since 2.9.1
+
+    @header{wx/debug.h}
+ */
+void wxSetDefaultAssertHandler();
+
 /**
     In debug mode (when @c __WXDEBUG__ is defined) this function generates a
     debugger exception meaning that the control is passed to the debugger if