new gensym handling (#11985)

* new .gensym implementation
* make astspec test green again
* introduce a --useVersion switch to group compatibility switches
* fixes #10180
* fixes #11494 
* fixes #11483
* object constructor fields and named parameters are also not gensym'ed
* disabled broken package

tests/template/tmore_regressions.nim

@@ -0,0 +1,44 @@
+discard """
+output: '''0
+
+0.0'''
+"""
+
+# bug #11494
+import macros
+
+macro staticForEach(arr: untyped, body: untyped): untyped =
+    result = newNimNode(nnkStmtList)
+
+    arr.expectKind(nnkBracket)
+    for n in arr:
+        let b = copyNimTree(body)
+        result.add quote do:
+            block:
+                type it {.inject.} = `n`
+                `b`
+
+template forEveryMatchingEntity*() =
+    staticForEach([int, string, float]):
+        var a: it
+        echo a
+
+forEveryMatchingEntity()
+
+
+# bug #11483
+proc main =
+  template first(body) =
+    template second: var int =
+      var o: int
+      var i  = addr(o)
+      i[]
+
+    body
+
+  first:
+    second = 5
+    second = 6
+
+main()
+