mk: avoid warnings for absent .depend.touch

Author: mtzguido

mk/fstar-12.mk

@@ -81,7 +81,7 @@ DEPSTEM := $(CACHE_DIR)/.depend$(TAG)
 $(DEPSTEM).touch: .force
 	mkdir -p $(dir $@)
 	find $(SRC) -name '*.fst*' > $@.chk
-	diff -q $@ $@.chk || cp $@.chk $@
+	diff -q $@ $@.chk 2>/dev/null || cp $@.chk $@
 
 $(DEPSTEM): $(DEPSTEM).touch
 	$(call msg, "DEPEND", $(SRC))

mk/lib.mk

@@ -141,7 +141,7 @@ DEPSTEM := $(CACHE_DIR)/.depend$(TAG)
 $(DEPSTEM).touch: .force
 	mkdir -p $(dir $@)
 	find $(SRC) -name '*.fst*' > $@.chk
-	diff -q $@ $@.chk || cp $@.chk $@
+	diff -q $@ $@.chk 2>/dev/null || cp $@.chk $@
 
 $(DEPSTEM): $(DEPSTEM).touch
 	$(call msg, "DEPEND", $(SRC))

mk/plugins.mk

@@ -125,7 +125,7 @@ DEPSTEM := $(CACHE_DIR)/.depend$(TAG)
 $(DEPSTEM).touch: .force
 	mkdir -p $(dir $@)
 	find $(SRC) -name '*.fst*' > $@.chk
-	diff -q $@ $@.chk || cp $@.chk $@
+	diff -q $@ $@.chk 2>/dev/null || cp $@.chk $@
 
 $(DEPSTEM): $(DEPSTEM).touch
 	$(call msg, "DEPEND", $(SRC))