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.
The c is the only letter that forms a double consonant in Spanish (the rr and ll are considered independent letters). The combination ch, pronounced like ch in cheese, was formally considered a separate letter of the Spanish alphabet (following c), but is now just thought of as a combination of consonants.