[configure] check and enforce why3 version

src/plugins/wp/configure.ac

@@ -56,8 +56,16 @@ REQUIRE_WHY3=
 USE_WHY3=
 HAS_WHY3=
 
+AC_MSG_CHECKING(for why3 (>= 1.3.1))
+WHY3VERSION=`ocamlfind query -format %v why3 | tr -d '\\r\\n'`
+case $WHY3VERSION in
+      0.* | 1.[[012]].* | 1.3.0)
+        AC_MSG_ERROR(found why3 $WHY3VERSION: requires 1.3.1 or higher.);;
+      *)
+        AC_MSG_RESULT(found $WHY3VERSION: should work);;
+esac
+
 WHY3_PATH=`ocamlfind query why3 | tr -d '\\r\\n'`
-echo "Ocamlfind -> using $WHY3_PATH"
 WHY3PATH_FOR_CONFIGURE=$WHY3_PATH
 
 configure_library([WHY3],