Variables starting with `e' in iokit/IOKit/hidsystem

• echo iokit/IOKit/hidsystem/Makefile:41
• EV_AUDIO_MAX_VOLUME iokit/IOKit/hidsystem/IOHIDShared.h:226
• eventType iokit/IOKit/hidsystem/IOHIKeyboard.h:46
• EXCLUDE_HEADERS iokit/IOKit/hidsystem/Makefile:24
• EXPORT_MI_DIR iokit/IOKit/hidsystem/Makefile:43
• expr iokit/IOKit/hidsystem/Makefile:44