Compilers are almost always written in C. This raises something of a "chicken and egg" problem-how was the first C compiler for a particular system created? If you need to create the first compiler for language X on system Y, one approach is to create a cross-compiler. A cross-compiler runs on system Z but generates code for system Y. Explain how, starting with a compiler for language X that runs on system Z, you might use cross-compilation to create a compiler for language X, written in X, that runs on system Y and generates code for system Y. What extra problems arise if system Y is "bare"-that is, has no operating system or compilers for any language? (Recall that Unix is written in C and thus must be compiled before its facilities can be used.)