@Override
	protected int getErrno(Errno err) {
		Integer errno = ERRNOS.get(err);
		if (errno == null) {
			throw new AssertionError("Do not know errno value for " + err);
		}
		return errno;
	}
Construct a new library

@param machine the machine emulating the hardware
@param fs the file system to export to the user-space program
@param program a program containing the syscall definitions and conventions, likely the
           target program
@param user the "current user" to simulate
Ghidra/Features/SystemEmulation/src/main/java/ghidra/pcode/emu/linux/AbstractEmuLinuxSyscallUseropLibrary.java