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@11061 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/list.h

@@ -485,8 +485,8 @@ class WXDLLEXPORT wxList : public wxObjectList
 {
 public:
     wxList(int key_type = wxKEY_NONE) : wxObjectList((wxKeyType)key_type) { }
-#ifdef __WXMAC_X__
-   ~wxList() {}   // Added min for Mac X
+#ifdef __DARWIN__
+   ~wxList() { }
 #endif
 
     wxList& operator=(const wxList& list)