Include <sys/ioctl.h>, <sys/resource.h> and <sys/wait.h> optionally. Though CloudABI implements a very large part of POSIX, it does not provide these header files, for the reason that there is no raw device access, no resource limiting and no access to the global process table through wait(). It looks like these header files are not actually needed in theory. There don't seem to be any constructs in these source files that use these features, but I suspect they might still be required on some systems.