Add Boost System library to all tests

I don't know what added this requirement, but this last night lots of
them started failing to link.
Also remove some obsolete commented-out stuff

indra/cmake/LLAddBuildTest.cmake

@@ -50,6 +50,7 @@ INCLUDE(GoogleMock)
     )
   SET(alltest_LIBRARIES
     ${GOOGLEMOCK_LIBRARIES}
+    ${BOOST_SYSTEM_LIBRARY}
     ${PTHREAD_LIBRARY}
     ${WINDOWS_LIBRARIES}
     )

indra/newview/CMakeLists.txt

@@ -2082,32 +2082,11 @@ if (LL_TESTS)
     LL_TEST_ADDITIONAL_LIBRARIES "${JSONCPP_LIBRARIES}"
   )
 
-  set_source_files_properties(
-    lllogininstance.cpp
-    PROPERTIES
-    LL_TEST_ADDITIONAL_LIBRARIES "${BOOST_SYSTEM_LIBRARY}"
-  )
-
-  ##################################################
-  # DISABLING PRECOMPILED HEADERS USAGE FOR TESTS
-  ##################################################
-  # if(USE_PRECOMPILED_HEADERS)
-  #     set_source_files_properties(
-  #       ${viewer_TEST_SOURCE_FILES}
-  #       PROPERTIES
-  #         LL_TEST_ADDITIONAL_SOURCE_FILES llviewerprecompiledheaders.cpp
-  #       )
-  # endif(USE_PRECOMPILED_HEADERS)
   LL_ADD_PROJECT_UNIT_TESTS(${VIEWER_BINARY_NAME} "${viewer_TEST_SOURCE_FILES}")
 
   #set(TEST_DEBUG on)
   set(test_sources llcapabilitylistener.cpp)
-  ##################################################
-  # DISABLING PRECOMPILED HEADERS USAGE FOR TESTS
-  ##################################################
-  # if(USE_PRECOMPILED_HEADERS)
-  #     set(test_sources "${test_sources}" llviewerprecompiledheaders.cpp)
-  # endif(USE_PRECOMPILED_HEADERS)
+
   set(test_libs
     ${LLMESSAGE_LIBRARIES}
     ${WINDOWS_LIBRARIES}