Compiler changes between RVCT v4.0 and ARM Compiler v4.1
Various changes have been made to armcc in ARM Compiler toolchain v4.1.
Sign rules on enumerators has changed in line with convention. Enumerator container is now unsigned unless a negative constant is defined. The RVCT v4.0 10Q1 patch made this change in GCC mode only.
-O3 no longer implies
--multifile option has always been available as a separate option and it
is recommended you put this into your builds.