Pin dune to work around compiler options split

ocaml/ocaml@51e5cf2 split the compiler
flags for native and bytecode compiler to separate flags. It also
changes the flag names which breaks builds of several packages. This
commit is a workaround for that change.

Makefile

@@ -111,6 +111,21 @@ ifeq (1, $(USE_SYS_DUNE_HACK))
 	opam install --switch=$(CONFIG_SWITCH_NAME) --yes "dune.$(SANDMARK_DUNE_VERSION)" "dune-configurator.$(SANDMARK_DUNE_VERSION)"
 	# Pin the version so it doesn't change when installing packages
 	opam pin add --switch=$(CONFIG_SWITCH_NAME) --yes -n dune "$(SANDMARK_DUNE_VERSION)"
+else
+	@{ case "$*" in \
+		5.3.*) \
+			opam repo add upstream "git+https://github.com/ocaml/opam-repository.git" --on-switch=$(CONFIG_SWITCH_NAME) --rank 2; \
+			opam install --switch=$(CONFIG_SWITCH_NAME) --yes ocamlfind; \
+			echo "Pinning dune to fixed version to work around binary and native compiler options split"; \
+			opam pin add --yes -n --switch=$(CONFIG_SWITCH_NAME) dune."$(SANDMARK_DUNE_VERSION)" https://github.com/punchagan/dune.git#fix-compiler-opts; \
+			opam pin add --yes -n --switch=$(CONFIG_SWITCH_NAME) dune-configurator."$(SANDMARK_DUNE_VERSION)" https://github.com/punchagan/dune.git#fix-compiler-opts; \
+			opam reinstall --switch=$(CONFIG_SWITCH_NAME) --yes dune dune-configurator ;; \
+		*) \
+			opam repo add upstream "git+https://github.com/ocaml/opam-repository.git" --on-switch=$(CONFIG_SWITCH_NAME) --rank 2; \
+			opam install --switch=$(CONFIG_SWITCH_NAME) --yes ocamlfind; \
+			opam install --switch=$(CONFIG_SWITCH_NAME) --yes "dune.$(SANDMARK_DUNE_VERSION)" "dune-configurator.$(SANDMARK_DUNE_VERSION)"; \
+			opam pin add --switch=$(CONFIG_SWITCH_NAME) --yes -n dune "$(SANDMARK_DUNE_VERSION)";; \
+	esac };
 endif
 
 ocamls=$(wildcard ocaml-versions/*.json)