Is __CC_ARM not defined in the MDK Eval Version?

I'm working on a simple project and trying to make it work for both STM32CubeIDE and Keil uVision.  Building in uVision, in *my* files __CC_ARM is not defined. If I manually define it on the Target1 Options C Compiler form, then I get a million errors says that it is already defined in *other* files. Other files meaning supplied things like

stm32f10x.h(483): warning: In file included from...

I can see that in "core_cm3.h" it is already defined (magically).

Ideas??

I noticed someone doing this:

#if defined(__CC_ARM) || defined(__ARMCC_VERSION)