FYI:
This is a report of the warnings one gets compiling C::B against wxWidgets 2.8.3 using MinGW GCC 3.4.5 with API 3.9
Terms:
  Main: the code compiled by project file CodeBlocks.cbp
  Contrib: the code compiled by workspace file ContribPlugins.workspace
  SDK: the code under folder src/sdk
  Main Plugins:the code under src/plugins, but NOT under src/plugins/contrib
  Contrib Plugins:the code under src/plugins/contrib
  Core: the code under src/src
Note: Testing done without ContribPlugins/CodeSnippets-msw because of errors when WXWIN_COMPATIBILITY_2_6=0.
Note: Testing done with the following patches applied.
      Berlios Patch 1907 disable_compat26 Fixes for 2.8 (XRC Patches)
      Berlios Patch 1908 disable_compat26 Fixes for 2.8 (SDK Patches)
      Berlios Patch 1911 disable_compat26 Fixes for 2.8 (Tools Patch)
      Berlios Patch 1897 personality=ask not working     
Note: Sometimes Berlios Patch 1788 "SDK patch to reduce warning for wxWidgets 2.8" is applied. 
With 2.6 compatible mode on (WXWIN_COMPATIBILITY_2_6=1, in lib\gcc_dll\mswu\wx\setup.h)
Without Berlios Patch 1788 "SDK patch to reduce warning for wxWidgets 2.8" applied.
Number      Area
 51         Main
 25         Contrib
 76         Total
Number      Section
  1         SDK/wxscintilla
 22         SDK other
  8         Core
  8         MainPlugins/Compiler
  3         MainPlugins/Debugger
  3         MainPlugins/Code-completion
  4         MainPlugins/Scripted wizard
  2         MainPlugins/To-do
  3         ContribPlugins/EnvVars Plug-In
  3         ContribPlugins/C::B KeyBinder
  8         ContribPlugins/Exporter/wxPdfDocument
 11         ContribPlugins/wxSmith
 ??         ContribPlugins/CodeSnippets-msw
 76         Total
With 2.6 compatible mode on (WXWIN_COMPATIBILITY_2_6=1, in lib\gcc_dll\mswu\wx\setup.h)
With Berlios Patch 1788 "SDK patch to reduce warning for wxWidgets 2.8" applied.
Number      Area
 29         Main
 25         Contrib
 54         Total
Number      Section
  1         SDK/wxscintilla
  0         SDK other
  8         Core
  8         MainPlugins/Compiler
  3         MainPlugins/Debugger
  3         MainPlugins/Code-completion
  4         MainPlugins/Scripted wizard
  2         MainPlugins/To-do
  3         ContribPlugins/EnvVars Plug-In
  3         ContribPlugins/C::B KeyBinder
  8         ContribPlugins/Exporter/wxPdfDocument
 11         ContribPlugins/wxSmith
 ??         ContribPlugins/CodeSnippets-msw
 54         Total
Tim S