This process was sometimes called linkage editing and the output known as a load module. A compiler works with what are sometimes called 3GL and higher-level languages. An assembler works on programs written using a processor's assembler language.
In general, however, when between vowels (as in exactamente) the Spanish x is pronounced like the English ks sound but softer or less explosive. When it comes before another consonant (as in expediciÃ³n), it has the s sound in some regions/countries but the soft ks sound in others.
I have only ever heard those terms used by Mexicans. I have never heard a South American use them. So it would be my son/ my daughter, and used as a term of affection in Mexican Spanish....... It just a contraction for mi hijo & mi hija. It does not mean they can't spell.