Implicit recursiveness and clean rule

All objects defining $(OBJS) will get them and *.a deleted during
make clean.

The all, clean and install rules now implicitly imply their -recursive
counterparts - those will just do nothing in case of $(SUBDIRS) not
defined, so that's ok.

Makefile.lib

@@ -58,6 +58,11 @@ endif
 %.a:
 	$(call cmd,archive)
 
+ifdef $(OBJS)
+clean:
+	rm -f $(OBJS) *.a
+endif
+
 
 # Recursion:
 
@@ -68,5 +73,9 @@ all-recursive install-recursive clean-recursive:
 		$(call ncmd,recmake) || exit 1; \
 	done
 
+all: all-recursive
+install: install-recursive
+clean: clean-recursive
+
 
 # vim:syntax=make