- avoid inline assembler, have more a inline bytecode adder
  explicit opcodes, e.g. nop -> .byte 0x90
- read -1 problem is the c4.c as interpreter reading behaving wrongly
  because -1 is wrongly handled in integer parsing
- variadic functions are not type-safe, do we need them?
  - printf -> putint, putchar, etc.
  - snprintf no option, strcat, strstr etc also not really
  - newer formating functions and logging: strfmon, error, warn, syslog
  - syscall