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.
You see, the X in Xmas did not originate as our English alphabet's X but as the symbol X in the Greek alphabet, called Chi, with a hard ch. The Greek Chi or X is the first letter in the Greek word Christos. Eric G. Gration claims that as early as the first century the X was used as Christ's initial.