attr: use generic autoreconf fixup

Use the generic autoreconf facility to pickup proper variants of
autoconf, automake and libtool.

Remove the unneeded Build/Prepare override.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

utils/attr/Makefile

@@ -19,10 +19,13 @@ PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
 PKG_SOURCE_VERSION:=$(PKG_REV)
 PKG_BUILD_DIR:=$(BUILD_DIR)/$(PKG_NAME)-$(PKG_VERSION)
 PKG_MAINTAINER:=Maxim Storchak <m.storchak@gmail.com>
-PKG_INSTALL:=1
+
 PKG_LICENSE:=LGPL-2.1 GPL-2.0
 PKG_LICENSE_FILES:=doc/COPYING doc/COPYING.LGPL
 
+PKG_INSTALL:=1
+PKG_FIXUP:=autoreconf
+
 include $(INCLUDE_DIR)/package.mk
 
 define Package/attr/Default
@@ -65,11 +68,6 @@ endef
 
 CONFIGURE_ARGS += --enable-static --enable-shared
 
-define Build/Prepare
-	$(call Build/Prepare/Default)
-	(cd $(PKG_BUILD_DIR); ./autogen.sh;);
-endef
-
 define Package/attr/install
 	$(INSTALL_DIR) $(1)/usr/bin
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/* $(1)/usr/bin/