previously I solved this via ifdef macros but with the files split we need a (nop) longdouble dispatcher to keep the logic out of loops .c.src
alternative I see would be to keep the old macros (NPY_HAVE_SIMD_TYPE) and preprocessor guard the run_simd dispatcher in loops.c.src.

having it a separate repeat block is just to save on #ifdefs in the actual vectorized repeat block.