I needed xxhash for a project, so created a Makefile. Should one of the Maintainers of the Util section want to take ownership of it to include in the master branch--Please do.
Enjoy.
$ cat feeds/packages/utils/xxhash/Makefile
#
# Copyright (C) 2006-2015 OpenWrt.org
#
# This is free software, licensed under the GNU General Public License v2.
# See /LICENSE for more information.
#
include $(TOPDIR)/rules.mk
PKG_NAME:=xxhash
PKG_VERSION:=0.8.1
PKG_RELEASE:=1
PKG_SOURCE:=$(PKG_NAME)_$(PKG_VERSION).tar.gz
PKG_SOURCE_URL:=https://github.com/Cyan4973/xxHash/archive/v$(PKG_VERSION)
PKG_HASH:=3bb6b7d6f30c591dd65aaaff1c8b7a5b94d81687998ca9400082c739a690436c
# The source for the library (xxhash.c and xxhash.h) is BSD
# The source for the command line tool (xxhsum.c) is GPLv2+
PKG_MAINTAINER:=https://github.com/Cyan4973/xxHash
PKG_LICENSE:=BSD and GPLv2+
PKG_LICENSE_FILES:=COPYING
include $(INCLUDE_DIR)/package.mk
define Package/xxhash/Default
SECTION:=utils
CATEGORY:=Utilities
URL:=http://www.xxhash.com
endef
define Package/xxhash
$(call Package/xxhash/Default)
TITLE:=Extremely fast hash algorithm
#DEPENDS:=+make +gcc
endef
define Package/xxhash/description
xxHash is an Extremely fast Hash algorithm, running at RAM speed
limits. It successfully completes the SMHasher test suite which
evaluates collision, dispersion and randomness qualities of hash
functions. Code is highly portable, and hashes are identical on all
platforms (little / big endian).
endef
define Build/Prepare
rm -rf $(PKG_BUILD_DIR)/
mkdir -p $(PKG_BUILD_DIR)/
$(TAR) -xzf $(DL_DIR)/$(PKG_SOURCE) -C $(PKG_BUILD_DIR) --strip 1
endef
define Build/InstallDev
$(INSTALL_DIR) $(1)/usr/include
$(CP) $(PKG_BUILD_DIR)/*.h $(1)/usr/include
$(INSTALL_DIR) $(1)/usr/lib
$(CP) $(PKG_BUILD_DIR)/libxxhash.so $(1)/usr/lib
$(INSTALL_DIR) $(1)/usr/lib/pkgconfig
$(CP) $(PKG_BUILD_DIR)/libxxhash.pc.in $(1)/usr/lib/pkgconfig
endef
define Package/xxhash/install
$(INSTALL_DIR) $(1)/usr/lib
$(CP) $(PKG_BUILD_DIR)/libxxhash.so* $(1)/usr/lib
$(INSTALL_DIR) $(1)/usr/bin
$(INSTALL_BIN) $(PKG_BUILD_DIR)/xxh*sum $(1)/usr/bin/
endef
$(eval $(call BuildPackage,xxhash))