Merge from SFTP.
Removed the --diag-supress ifdef, as it was only due to me not being able to spell --diag_suppress! (which is supported on all versions of RVCT)
Added FSHELL_[NO_]ARMCC_DIAG_SUPPRESS_SUPPORT.
The versions of RVCT that I'm using (2.2 build 616 and 2.2 build 686) don't appear to support --diag-supress.