mk/checkconf.mk: update generation of conf.mk

Make generation of conf.mk more consistent with what we do for conf.h,
that is:
- conf.mk shall not be touched if its content does not change,
- write "CHK" when checking the file, then "UPD" only if it needs
updating.

Signed-off-by: Jerome Forissier <[email protected]>
Reviewed-by: Jens Wiklander <[email protected]>
Reviewed-by: Pascal Brand <[email protected]>

core/core.mk

@@ -44,7 +44,7 @@ $(conf-file): FORCE
 	$(call check-conf-h)
 
 $(conf-mk-file):  FORCE
-	$(call build-conf-mk)
+	$(call check-conf-mk)
 
 #
 # Do libraries

mk/checkconf.mk

@@ -23,16 +23,12 @@ define check-conf-h
 	echo "#define $${guard}" >>[email protected];			\
 	echo -n "$${cnf}" | sed 's/_nl_ */\n/g' >>[email protected];	\
 	echo "#endif" >>[email protected];					\
-	if [ -r $@ ] && cmp -s $@ [email protected]; then			\
-		rm -f [email protected];					\
-	else							\
-		echo '  UPD     $@';				\
-		mv [email protected] $@;					\
-	fi
+	$(call mv-if-changed,[email protected],$@)
 endef
 
-define build-conf-mk
+define check-conf-mk
 	$(q)set -e;						\
+	echo '  CHK     $@';					\
 	cnf="$(strip $(foreach var,				\
 		$(call cfg-vars-by-prefix,CFG_),		\
 		$(call cfg-make-variable,$(var))))";		\
@@ -43,8 +39,17 @@ define build-conf-mk
 	echo "PLATFORM=${PLATFORM}" >>[email protected];			\
 	echo "PLATFORM_FLAVOR=${PLATFORM_FLAVOR}" >>[email protected]; 	\
 	echo -n "$${cnf}" | sed 's/_nl_ */\n/g' >>[email protected];	\
-	echo '  UPD     $@';					\
-	mv [email protected] $@;
+	$(call mv-if-changed,[email protected],$@)
+endef
+
+# Rename $1 to $2 only if file content differs. Otherwise just delete $1.
+define mv-if-changed
+	if [ -r $2 ] && cmp -s $2 $1; then			\
+		rm -f $1;					\
+	else							\
+		echo '  UPD     $2';				\
+		mv $1 $2;					\
+	fi
 endef
 
 define cfg-vars-by-prefix