[PATCH v1 1/7] tools/ocaml/Makefile: do not run ocamldep during make clean

[Edwin Török <edvin.torok@xxxxxxxxxx>]

Trying to include .ocamldep.make will cause it to be generated if it
doesn't exist.
We do not want this during make clean: we would remove it anyway.

Speeds up make clean.

Before (measured on f732240fd3bac25116151db5ddeb7203b62e85ce, July 2022):
```
Parsing 
/home/edwin/xen2/tools/ocaml/libs/xl/../../../../tools/libs/light/libxl_types.idl
Parsing 
/home/edwin/xen2/tools/ocaml/libs/xl/../../../../tools/libs/light/libxl_types.idl
Parsing 
/home/edwin/xen2/tools/ocaml/libs/xl/../../../../tools/libs/light/libxl_types.idl
Parsing 
/home/edwin/xen2/tools/ocaml/libs/xl/../../../../tools/libs/light/libxl_types.idl
Parsing 
/home/edwin/xen2/tools/ocaml/libs/xl/../../../../tools/libs/light/libxl_types.idl

 Performance counter stats for 'make clean -j8 -s' (5 runs):

            4.2233 +- 0.0208 seconds time elapsed  ( +-  0.49% )
```

After:
```
perf stat -r 5 --null make clean -j8 -s

 Performance counter stats for 'make clean -j8 -s' (5 runs):

            2.7325 +- 0.0138 seconds time elapsed  ( +-  0.51% )
```

No functional change.

Signed-off-by: Edwin Török <edvin.torok@xxxxxxxxxx>
---
 tools/ocaml/Makefile.rules | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/ocaml/Makefile.rules b/tools/ocaml/Makefile.rules
index 7e4db457a1..d368308d9b 100644
--- a/tools/ocaml/Makefile.rules
+++ b/tools/ocaml/Makefile.rules
@@ -44,8 +44,10 @@ META: META.in
 
 ALL_OCAML_OBJ_SOURCES=$(addsuffix .ml, $(ALL_OCAML_OBJS))
 
+ifneq ($(MAKECMDGOALS),clean)
 .ocamldep.make: $(ALL_OCAML_OBJ_SOURCES) Makefile 
$(OCAML_TOPLEVEL)/Makefile.rules
        $(call quiet-command, $(OCAMLDEP) $(ALL_OCAML_OBJ_SOURCES) *.mli 
$o,MLDEP,)
+endif
 
 clean: $(CLEAN_HOOKS)
        $(Q)rm -f .*.d *.o *.so *.a *.cmo *.cmi *.cma *.cmx *.cmxa *.annot 
*.spot *.spit $(LIBS) $(PROGRAMS) $(GENERATED_FILES) .ocamldep.make META
-- 
2.34.1