The bytecode backend (used by ghci, TH, runghc) uses a separate loader; compiling uses the system loader.  Either way, though, the system's dynamic loader (which is invoked very early in initializing a new program) is always used because system libraries are usually shared; on ELF systems, it's also the "interpreter" for compiled programs so is unavoidable.  (I don't know if something similar is true for Mach-O.)