modified configure to allow configuration of wxMotif under Darwin/Mac OS X

wxWindows can be configured as wxMac or wxMotif under Mac OS X
replaced __WXMAC_X__ define by __DARWIN__ (general Darwin related issues)
moved dlopen/dlerror code to dynlib.cpp to make it available for wxMotif


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11065 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/mac/notebmac.cpp

@@ -32,7 +32,7 @@
 // check that the page index is valid
 #define IS_VALID_PAGE(nPage) (((nPage) >= 0) && ((nPage) < GetPageCount()))
 
-#ifdef __WXMAC_X__
+#ifdef __DARWIN__
   // I got these values for Mac OS X from the Appearance mgr docs. (Mark Newsam)
 const short kwxMacTabLeftMargin = 20 ;
 const short kwxMacTabTopMargin = 38 ;
@@ -76,7 +76,7 @@ IMPLEMENT_DYNAMIC_CLASS(wxNotebookEvent, wxCommandEvent)
 // common part of all ctors
 void wxNotebook::Init()
 {
-#ifdef __WXMAC_X__
+#ifdef __DARWIN__
     m_macHorizontalBorder = 7;
     m_macVerticalBorder = 8;
 #endif