[dune] Compile debug and checker printers.

As noted by Gäetan, we didn't compile these. We also provide a recipe
to run `ocamldebug`. Try (after a build):

```
dune exec dev/dune-dbg
(ocd) source dune_db
```

or

```
dune exec dev/dune-dbg checker
(ocd) source checker_dune_db
```

for the checker.

1 files changed, 11 insertions, 0 deletions

diff --git a/dev/dune-dbg.in b/dev/dune-dbg.in
new file mode 100755
index 0000000000..464e026400
--- /dev/null
+++ b/dev/dune-dbg.in
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+# Run in a proper install dune env.
+case $1 in
+checker)
+  ocamldebug `ocamlfind query -recursive -i-format coq.checker_printers` -I +threads -I dev _build/default/checker/main.bc
+  ;;
+*)
+  ocamldebug `ocamlfind query -recursive -i-format coq.top_printers` -I +threads -I dev _build/default/topbin/coqtop_byte_bin.bc
+  ;;
+esac