cmake - CMake が必要なライブラリを見つけられない

Question

これは私の CMakeLists.txt です:

cmake_minimum_required(VERSION 2.6)

# Locate GTest
find_package(GTest REQUIRED)
include_directories(/usr/include/gtest)

# Link runTests with what we want to test and the GTest and pthread library
add_executable(runTests gtest.cpp)
target_link_libraries(runTests /usr/lib/gtest pthread)

cmake を実行すると、次のエラーが表示されます。

michael@michaelFriko:~/workspace/gtest/src$ cmake CMakeLists.txt
CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:97 (message):
  Could NOT find GTest (missing: GTEST_LIBRARY GTEST_MAIN_LIBRARY)
Call Stack (most recent call first):
  /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:291 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-2.8/Modules/FindGTest.cmake:150 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:8 (find_package)

これを解決するには？