Clean and fix definitions of options.

- Provide new helper functions in `Goptions` on the model of
  `declare_bool_option_and_ref`;

- Use these helper functions in many parts of the code base
  (encapsulates the corresponding references);

- Move almost all options from `declare_string_option` to
  `declare_stringopt_option` (only "Warnings" continue to use the
  former).  This means that these options now support `Unset` to get
  back to the default setting.  Note that there is a naming
  misalignment since `declare_int_option` is similar to
  `declare_stringopt_option` and supports `Unset`.  When "Warning" is
  eventually migrated to support `Unset` as well, we can remove
  `declare_string_option` and rename `declare_stringopt_option` to
  `declare_string_option`.

- For some vernac options and flags that have an equivalent
  command-line option or flag, implement it like the standard `-set`
  and `-unset`.

1 files changed, 6 insertions, 3 deletions

diff --git a/engine/uState.ml b/engine/uState.ml
index d532129dc5..ff85f09efa 100644
--- a/engine/uState.ml
+++ b/engine/uState.ml
@@ -176,8 +176,11 @@ let instantiate_variable l b v =
 
 exception UniversesDiffer
 
-let drop_weak_constraints = ref false
-
+let drop_weak_constraints =
+  Goptions.declare_bool_option_and_ref
+    ~depr:false
+    ~key:["Cumulativity";"Weak";"Constraints"]
+    ~value:false
 
 let process_universe_constraints ctx cstrs =
   let open UnivSubst in
@@ -270,7 +273,7 @@ let process_universe_constraints ctx cstrs =
           | ULub (l, r) ->
               equalize_variables true (Universe.make l) l (Universe.make r) r local
           | UWeak (l, r) ->
-            if not !drop_weak_constraints then weak := UPairSet.add (l,r) !weak; local
+            if not (drop_weak_constraints ()) then weak := UPairSet.add (l,r) !weak; local
           | UEq (l, r) -> equalize_universes l r local
   in
   let local =