rules.mk: Revise shared object rules

- selective install for shared libs
  - Kick out match all rule for directories

make/rules.mk

@@ -40,8 +40,8 @@ $(EXE): $(OBJ) $(LIB)
 $(LIBS):
 	make -C $(LIBDIR) all
 
-$(PREFIX) $(PREFIX)/%:
-	mkdir -p $@
+$(PREFIX)/lib/%.so: %.so
+	$(INSTALL) $< $@
 
 checkroot:
 	@if [ "$(CHECK_ROOT)" = true -o "$(CHECK_ROOT)" = TRUE ] ; then \
@@ -53,8 +53,7 @@ checkroot:
 installexe: all checkroot $(PREFIX)/bin
 	$(INSTALL) $(EXE) $(PREFIX)/bin/
 
-installso: all checkroot $(PREFIX)/lib
-	$(INSTALL) $(SHOBJS) $(PREFIX)/lib/
+installso: all checkroot $(PREFIX)/lib $(INSTALLED_SHOBJS)
 
 installsh: all checkroot $(PREFIX)/bin
 	$(INSTALL) $(SHSCRIPTS) $(PREFIX)/bin/