use DTD on the Why3 web page

Makefile.in

@@ -474,8 +474,7 @@ gallery::
 
 xml-validate:
 	@for x in `find examples/ -name why3session.xml`; do \
-	  xmllint --noout --dtdvalid share/why3session.dtd \
-			$$x 2>&1 | head -1; \
+	  xmllint --noout --valid $$x 2>&1 | head -1; \
 	done
 
 ########

examples/bitvectors/bitvector/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bitvectors/double/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bitvectors/double_of_int/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bitvectors/neg_as_xor/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bitvectors/power2/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/12475/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/12934/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/13375/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/13849/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/13853/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/13854/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/bts/fsetint/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/ac/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/array/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/bool/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/euclideandivision/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/floats/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/int/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"

examples/check-builtin/intreal/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/home/marche/why3/share/why3session.dtd">
+<!DOCTYPE why3session PUBLIC "-//Why3//proof session v2//EN" "http://why3.lri.fr/why3session.dtd">
 <why3session shape_version="2">
  <prover
   id="0"