bring back Coq 8.16 test; fix coq_makefile warning

.gitlab-ci.yml

@@ -33,7 +33,13 @@ build-coq.8.17.0:
   <<: *template
   variables:
     OPAM_PINS: "coq version 8.17.0"
-    #DENY_WARNINGS: "1" # coq_makefile warning cannot be resolved while supporting Coq 8.14
+    DENY_WARNINGS: "1"
+
+build-coq.8.16.1:
+  <<: *template
+  variables:
+    OPAM_PINS: "coq version 8.16.1"
+    DENY_WARNINGS: "1"
 
 trigger-iris.dev:
   <<: *template

README.md

@@ -21,7 +21,7 @@ To log in, you need to [create an MPI-SWS GitLab account](https://gitlab.mpi-sws
 
 For the tutorial material you need to have the following dependencies installed:
 
-- Coq 8.17.0
+- Coq 8.16.1 / 8.17.0
 - A development version of [Iris](https://gitlab.mpi-sws.org/iris/iris)
 
 *Note:* the tutorial material will not work with earlier or later versions of

_CoqProject

 -Q exercises exercises
 -Q solutions solutions
 -Q talks/demo demo
-INSTALLDEFAULTROOT = tutorial-popl21
+-docroot tutorial-popl21
 
 talks/demo/demo.v
 exercises/ex_01_swap.v