CPP: Add "system" as a Boost component.

This is required with newer Boost (starting with 1.50).

R=daniel@pocock.pro
BUG=

Review URL: https://codereview.appspot.com/100910043

cpp/CMakeLists.txt

@@ -87,9 +87,9 @@ if (${USE_BOOST} STREQUAL "ON")
   if (WIN32)
     set (Boost_USE_STATIC_LIBS ON)
   endif ()
-  find_package (Boost 1.40.0 COMPONENTS date_time thread)
+  find_package (Boost 1.40.0 COMPONENTS date_time system thread)
   if (NOT Boost_FOUND)
-    print_error ("Boost Datetime/Thread" "Boost")
+    print_error ("Boost Date_Time/System/Thread" "Boost")
   endif ()
   include_directories (${Boost_INCLUDE_DIRS})
 endif ()

debian/control

@@ -7,6 +7,7 @@ Build-Depends: ant,
                default-jdk | java-sdk,
                javahelper (>= 0.34),
                libboost-dev (>= 1.40),
+               libboost-system-dev (>= 1.40),
                libboost-thread-dev (>= 1.40),
                libgtest-dev,
                libicu-dev (>= 4.4),