valgrind reported invalid reads/writes with glibc err[x]|warn[x] (in
glibc printf) when stdio had been redirected in between.
define _progname (pointing to argv[0])
wrap some libc functions that do system calls (terminal output)
wrap read/write with syscall guard
define real_read/write (next dynamic linker find for read/write)
guard system calls in remaining code
introduce native_internhal.h
throw out some debug statements that break things
clean up includes a bit
declare board_init in native_internhal.h
add -ldl to LINKFLAGS for cpu/syscalls
