The declaration of the FMAP SFR at 0x9F is missing from device/include/mcs51/cc2430.h
Even though it's aliased to MEMCTR.FMAP, I think it is useful to have it declared.
CC2430 Data Sheet (rev. 2.1) SWRS036F - Sec 11.2.5 - p41
Applied in SDCC 3.0.6 #7013. Thank you.