ARM: Unknown ARM Architecture with RTX5

Using Keil MDK V5.24 for NXP LPC1343 with CMSIS RTX5. A #define "__ARM_ARCH_7M__" is missing in - maybe -"RTE_Components.h" (or in "LPC13xx.h" or in "system_LPC13xx.h" or in "core_cm3.h"). This then is flagged as error in "core_cm.h", line 53. How to get ARM architecture defined ? Best regards, Juergen.