Updated platform specific #if's to report unimplemented code when compiling with FL_PORTING defined and WIN32 and __APPLE__ undefined>

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@10989 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

FL/Fl_Copy_Surface.H

@@ -64,6 +64,9 @@ private:
 #elif defined(WIN32)
   HDC oldgc;
   HDC gc;
+#elif defined(FL_PORTING)
+# pragma message "FL_PORTING: define variables to hold a native offscreen bitmap in Fl_Copy_Surface"
+  // no default implementation
 #else // Xlib
   Fl_Offscreen xid;
   Window oldwindow;
@@ -115,6 +118,10 @@ public:
   virtual ~Fl_GDI_Surface_();
 };
 
+#elif defined(FL_PORTING)
+
+# pragma message "FL_PORTING: define a drawing surface for your platform"
+
 #elif !defined(FL_DOXYGEN)
 
 /* Xlib class to implement translate()/untranslate() */