This header was clearly copied from the common syscall.h and customized, but the header comment is no longer accurate -- this isn't the general file anymore.
* arm/redboot-syscalls.c (_close): Fix setting of errno value. (_lseek): Ditto. (_open): Ditto. (_write): Ditto. (_read): Ditto. (_rename): New function. (_system): Ditto. (_stat): Ditto. (_unlink): Call a syscall for this now. (isatty): Ditto. (_fstat): Ditto. (_gettimeofday): Ditto.