Hi,
finally I understand how the OpenWrt Makefiles for perl work.
Here is the Makefile for Crypt-Rijndael:
# $Id$
include $(TOPDIR)/rules.mk
PKG_NAME:=perl-crypt-rijndael
PKG_VERSION:=1.06
PKG_RELEASE:=1
PKG_MD5SUM:=adba5ba76f086d691a02021a3569a8e4
PKG_SOURCE_URL:=http://search.cpan.org/CPAN/authors/id/B/BD/BDFOY
PKG_SOURCE:=Crypt-Rijndael-$(PKG_VERSION).tar.gz
PKG_CAT:=zcat
PKG_BUILD_DIR:=$(BUILD_DIR)/perl/Crypt-Rijndael-$(PKG_VERSION)
include $(INCLUDE_DIR)/package.mk
include ../perl/perlmod.mk
define Package/perl-crypt-rijndael
SUBMENU:=Perl
SECTION:=lang
CATEGORY:=Languages
TITLE:=CBC compliant Rijndael encryption module
URL:=http://search.cpan.org/dist/Crypt-Rijndael/
DEPENDS:=perl
endef
define Build/Configure
$(call perlmod/Configure,,)
endef
define Build/Compile
$(call perlmod/Compile,,)
endef
define Package/perl-crypt-rijndael/install
$(call perlmod/Install,$(1),Crypt auto/Crypt)
endef
$(eval $(call BuildPackage,perl-crypt-rijndael))
Regards, Artem