isinf, isnan with armclang compiler

Using armclang compiler v6.22 for an stm32f4 (Cortex-M4) processor.  It appears that there's a compiler option -Wnan-infinity-disabled that's causing these functions to not work (substitutes with 'false').  I don't see this option in the Keil uVision settings to turn it off.  Is there a way to disable this option?  I've tried every optimization setting to no avail.