Fix for Github issue #103

Use CMAKE_THREAD_LIBS_INIT instead of pthread in sample_app.
The separate pthread library doesn't exist on Android.

Change-Id: I9a363ba7d29d2673359349f5f4288844f0550946
diff --git a/samples/CMakeLists.txt b/samples/CMakeLists.txt
index 3009ac9..5716054 100644
--- a/samples/CMakeLists.txt
+++ b/samples/CMakeLists.txt
@@ -1,4 +1,4 @@
 if(BUILD_SAMPLE_APP)
     add_executable(SimpleSample SimpleSample.cpp)
-    target_link_libraries(SimpleSample armnn pthread)
+    target_link_libraries(SimpleSample armnn ${CMAKE_THREAD_LIBS_INIT})
 endif()