Make the libraries module a hard dependency

Would it be OK to make the library module a hard dependency?

This would allow to simplify the code and avoid some duplication, for example right now _syntaxhighlighter_scan_lib_location() basically duplicates what libraries_get_path() does.

This would make even more sense long-term if we register the syntaxhihglighter external library with the Libraries Registry project.

I also have a doubt about caching syntaxhighlighter_lib_location in a variable, does this bring an actual benefit?
Scanning for the path on the filesystem for the library location only happens in a few places in the code, and most hooks implementations should be already cached by Drupal.