On Arch Linux ARM, -DCOMPILEWITH_NOTIFY was getting added immediately onto the end of the last include path in NOTIFY_CFLAGS without an intervening space and thus didn't get interpreted correctly as a separate option. Probably didn't matter on some other systems since NOTIFY_CFLAGS might have already ended in a space.
On Arch Linux ARM, -DCOMPILEWITH_NOTIFY was getting added immediately onto the end of the last include path in NOTIFY_CFLAGS without an intervening space and thus didn't get interpreted correctly as a separate option. Probably didn't matter on some other systems since NOTIFY_CFLAGS might have already ended in a space.