Rename faust_dsp to dsp_fname.
Replace ''.join(f.readlines()) with f.read().

Replace ''.join(f.readlines()) with f.read() because the first is just so
unnecessarily complex.
Rename FAUSTC to c_file and faust_c to c_fname.
Use check_output() to avoid intermediate C file.

Replace check_call() with check_output() in order to avoid an intermediate C file.