Hi, C::B devs:

Here is a modified function to retrieve all GCC default compiler directories

wxArrayString NativeParser::GetGCCCompilerDirs(const wxString &cpp_compiler, const wxString &base)
{
    wxArrayString gcc_compiler_dirs;

    // for starters , only do this for gnu compiler
    //Manager::Get()->GetLogManager()->DebugLog(_T("CompilerID ") + CompilerID);
    //
    //   windows: mingw32-g++ -v -E -x c++ nul
    //   linux  : g++ -v -E -x c++ /dev/null
    // do the trick only for c++, not needed then for C (since this is a subset of C++)


    // let's construct the command
    // use a null file handler
    // both works fine in Windows and linux

#ifdef __WXMSW__
    wxString Command = cpp_compiler + _T(" -v -E -x c++ nul");
#else
    wxString Command = cpp_compiler + _T(" -v -E -x c++ /dev/null");
#endif

    // action time  (everything shows up on the error stream
    wxArrayString Output, Errors;
    wxExecute(Command, Output, Errors, wxEXEC_NODISABLE);
    int nCount = Errors.GetCount();
    // the include dir (1 per line) show up between the lines
    // #include <...> search starts here:
    // End of search list
    //   let's hope this does not change too quickly, otherwise we need
    // to adjust our search code (for several versions ...)
    bool bStart = false;
    for(int idxCount = 0; idxCount < nCount; ++idxCount)
    {
        if (!bStart && Errors[idxCount] == _("#include <...> search starts here:"))
        {
            bStart = true;
        }
        else if (bStart && Errors[idxCount] == _("End of search list."))
        {
            bStart = false; // could jump out of for loop if we want
        }
        else if (bStart)
        {
//                Manager::Get()->GetLogManager()->DebugLog("include dir " + Errors[idxCount]);
            // get rid of the leading space (more general : any whitespace)in front
            wxRegEx reg(_T("^[ \t]*(.*)"));
            if(reg.Matches(Errors[idxCount]))
            {
                wxString out = reg.GetMatch(Errors[idxCount], 1);
                if(!out.IsEmpty())
                {
                    wxFileName dir(out);
                    if (NormalizePath(dir,base))
                    {
                        Manager::Get()->GetLogManager()->DebugLog(_T("Caching GCC dir: ") + dir.GetFullPath());
                        gcc_compiler_dirs.Add(dir.GetFullPath());
                    }
                    else
                    #if wxCHECK_VERSION(2, 9, 0)
                        Manager::Get()->GetLogManager()->DebugLog(F(_T("Error normalizing path: '%s' from '%s'"),out.wx_str(),base.wx_str()));
                    #else
                        Manager::Get()->GetLogManager()->DebugLog(F(_T("Error normalizing path: '%s' from '%s'"),out.c_str(),base.c_str()));
                    #endif
                }
            }
        }
    } // end for : idx : idxCount



    return gcc_compiler_dirs;
}


I have tested them at least works fine under Windows MinGW.

see the discussing in 

http://forums.codeblocks.org/index.php/topic,10598.0.html