adding #include "ImathPlatform.h" /* [i_a] M_PI_2 */ to define M_PI_2 for those platforms that haven't got it in the standard run-time lib
adding
#include "ImathPlatform.h" /* [i_a] M_PI_2 */
to define M_PI_2 for those platforms that haven't got it in the standard run-time lib

aforsythe/IlmBase,aforsythe/IlmBase,aforsythe/IlmBase,aforsythe/IlmBase