title: How to get CMake to recognize pthread on Ubuntu?
body: <p>If I compile on the command-line with g++ directly, I can see everything I need is there:</p>
  
  <pre><code>$ g++ -pthread test.cpp
  $ ldd a.out
      linux-vdso.so.1 =&gt;  (0x00007fffd05b3000)
      libstdc++.so.6 =&gt; /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f4a1ba8d000)
      libpthread.so.0 =&gt; /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f4a1b870000)
      ...more...
  </code></pre>
  
  <p>Then I try to create a simple cmake file for this 5-line test app:</p>
  
  <pre><code>$ cat CMakeLists.txt 
  PROJECT ( Test CXX )
  CMAKE_MINIMUM_REQUIRED ( VERSION 2.8 )
  FIND_PACKAGE ( Threads REQUIRED )
  ADD_EXECUTABLE ( test test.cpp )
  TARGET_LINK_LIBRARIES ( test ${CMAKE_THREAD_LIBS_INIT} )
  </code></pre>
  
  <p>However, I cannot figure out why CMake doesn't find what it needs to use for <code>Threads</code>:</p>
  
  <pre><code>$ cd build/
  $ cmake ..
  CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:97 (MESSAGE):
    Could NOT find Threads (missing: Threads_FOUND)
  Call Stack (most recent call first):
    /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:288 (_FPHSA_FAILURE_MESSAGE)
    /usr/share/cmake-2.8/Modules/FindThreads.cmake:166 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
    CMakeLists.txt:4 (FIND_PACKAGE)
  -- Configuring incomplete, errors occurred!
  </code></pre>