Generify source code

Previously we would fail in some parts of the code if we did not have a
premade configuration, now we use any code that was marked as Linux, BSD and
Solaris as our basis in order to support building unknown Unix systems.

cde/programs/dtwm/WmFunction.c

@@ -98,7 +98,7 @@ extern XmMenuState _XmGetMenuState();
 
 static unsigned int GetEventInverseMask(XEvent *event);
 
-#if (defined(__linux__) || defined(sun) || defined(CSRG_BASED)) && !defined(_NFILE)
+#if !defined(_NFILE)
 #define _NFILE FOPEN_MAX
 #endif