Merge branch 'v8.5' into trunk

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diff --git a/plugins/extraction/ExtrHaskellZInteger.v b/plugins/extraction/ExtrHaskellZInteger.v
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+(** Extraction of [Z] into Haskell's [Integer] *)
+
+Require Import ZArith.
+Require Import ExtrHaskellZNum.
+
+(** Disclaimer: trying to obtain efficient certified programs
+    by extracting [Z] into [Integer] isn't necessarily a good idea.
+    See comments in [ExtrOcamlNatInt.v].
+*)
+
+Extract Inductive positive => "Prelude.Integer" [
+  "(\x -> 2 Prelude.* x Prelude.+ 1)"
+  "(\x -> 2 Prelude.* x)"
+  "1" ]
+  "(\fI fO fH n -> if n Prelude.== 1 then fH () else
+                   if Prelude.odd n
+                   then fI (n `Prelude.div` 2)
+                   else fO (n `Prelude.div` 2))".
+
+Extract Inductive Z => "Prelude.Integer" [ "0" "(\x -> x)" "Prelude.negate" ]
+  "(\fO fP fN n -> if n Prelude.== 0 then fO () else
+                   if n Prelude.> 0 then fP n else
+                   fN (Prelude.negate n))".