distinguish between 'reorder' and 'noforward'

tests/modules/treorder.nim

@@ -0,0 +1,42 @@
+discard """
+  cmd: "nim -d:testdef $target $file"
+  output: '''works 34
+34
+defined
+first impl'''
+"""
+
+{.reorder: on.}
+
+{.push callconv: stdcall.}
+proc bar(x: T)
+
+proc foo() =
+  bar(34)
+  whendep()
+
+proc foo(dummy: int) = echo dummy
+
+proc bar(x: T) =
+  echo "works ", x
+  foo(x)
+
+foo()
+
+type
+  T = int
+
+when defined(testdef):
+  proc whendep() = echo "defined"
+else:
+  proc whendep() = echo "undefined"
+
+when not declared(goo):
+  proc goo() = echo "first impl"
+
+when not declared(goo):
+  proc goo() = echo "second impl"
+
+goo()
+
+{.pop.}