Adding farmhash package from google (#3239)

* Adding farmhash package from google

var/spack/repos/builtin/packages/farmhash/CMakeLists.txt

@@ -0,0 +1,25 @@
+cmake_minimum_required(VERSION 2.8.3)
+
+project(farmhash)
+
+set(FARMHASH_SRCS
+    "src/farmhash.h"
+    "src/farmhash.cc"
+)
+
+set(FARMHASH_INCLUDES
+    "src/farmhash.h"
+)
+
+include_directories("${CMAKE_CURRENT_SOURCE_DIR}")
+
+add_library(farmhash ${FARMHASH_SRCS})
+add_definitions(-DFARMHASH_NO_BUILTIN_EXPECT)
+
+install(TARGETS farmhash
+  LIBRARY DESTINATION lib COMPONENT RuntimeLibraries
+  ARCHIVE DESTINATION lib COMPONENT Development)
+
+foreach(FARMHASH_INCLUDE ${FARMHASH_INCLUDES})
+  install(FILES ${FARMHASH_INCLUDE} DESTINATION include COMPONENT Development)
+endforeach()

var/spack/repos/builtin/packages/farmhash/package.py

@@ -0,0 +1,42 @@
+##############################################################################
+# Copyright (c) 2013-2016, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+import os.path
+from shutil import copyfile
+
+
+class Farmhash(CMakePackage):
+    """
+    FarmHash provides hash functions for strings and other data.
+    """
+
+    homepage = "https://github.com/google/farmhash"
+
+    version('92e897', git='https://github.com/google/farmhash.git', 
+            commit='92e897b282426729f4724d91a637596c7e2fe28f')
+
+    def patch(self):
+        copyfile(join_path(os.path.dirname(__file__), "CMakeLists.txt"),
+                 "CMakeLists.txt")