xen: Added support to build agent in xen builder - Added platform detection setting to selectively turn off Wno-unused-local-typedefs for gcc 4.1.2 - Reverted changed in GetBuildInfo() as GCC 4.1.2 complained witha warning, 'type always evaluates to true' - Fix in agent_param.cc, ~AgentParam() [Praveen] - Fix in return data type CalculateBandwidth() - Fix in data type comparison in test_vgw.cc

Signed-off-by: Anirban Chakraborty <abchak@juniper.net>