handling of compiler procs improved for DLL generation

lib/nimrtl.nim

@@ -0,0 +1,39 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2010 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Main file to generate a DLL from the standard library. 
+## The default Nimrtl does not only contain the ``system`` module, but these 
+## too:
+##
+## * strutils
+## * parseutils
+## * parseopt
+## * parsecfg
+## * strtabs
+## * times
+## * os
+## * osproc
+## * pegs
+## * unicode
+## * ropes
+## * re
+## 
+## So the resulting dynamic library is quite big. However, it is very easy to
+## strip modules out. Just modify the ``import`` statement in
+## ``lib/nimrtl.nim`` and recompile. Note that simply *adding* a module
+## here is not sufficient, though.
+
+when system.appType != "lib":
+  {.error: "This file has to be compiled as a library!".}
+
+when not defined(createNimRtl): 
+  {.error: "This file has to be compiled with '-d:createNimRtl'".}
+
+
+