sdbfs: added toplevel Makefile; */Makefile: support all targets

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

sdbfs/Makefile

+
+DIRS = kernel lib userspace doc
+
+all clean modules install modules_install:
+	for d in $(DIRS); do $(MAKE) -C $$d $@ || exit 1; done

sdbfs/doc/Makefile

@@ -56,5 +56,5 @@ terse:
 clean: terse
 	rm -f $(ALL) $(TEXI)
 
-install:
-
+# add the other unused targets, so the rule in ../Makefile works
+modules install modules_install:

sdbfs/lib/Makefile

@@ -38,3 +38,6 @@ $(LIB): $(OBJS)
 
 clean:
 	rm -f $(OBJS) $(LIB) *~ core
+
+# add the other unused targets, so the rule in ../Makefile works
+modules install modules_install:

sdbfs/userspace/Makefile

@@ -24,3 +24,6 @@ $(PROG): ../lib/libsdbfs.a
 
 clean:
 	rm -f $(PROG) *.o *~ core
+
+# add the other unused targets, so the rule in ../Makefile works
+modules install modules_install: