[boost] [1.35] System: error_code.cpp #defines macros without checking if already defined

Hi Beman, error_code.cpp contains the following #defines: #define _CRT_SECURE_NO_DEPRECATE #define _SCL_SECURE_NO_DEPRECATE It should first check that these macros are not defined already. Otherwise users who #define these macros on the command line will received duplicate definition errors, as I am. Also, you might consider adding: #define _SECURE_SCL 0 for VC 9. - Mat