Another round of tweaks for spandsp. There should be no functional changes,

although quite a few things have changed in the test suite

libs/spandsp/tests/awgn_tests.c

@@ -90,7 +90,7 @@ int main(int argc, char *argv[])
         }
         error = 100.0*(1.0 - sqrt(total/total_samples)/noise_source.rms);
         printf("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
-               log10(sqrt(total/total_samples)/32768.0)*20.0 + DBM0_MAX_POWER,
+               10.0*log10((total/total_samples)/(32768.0*32768.0) + 1.0e-10) + DBM0_MAX_POWER,
                j,
                error,
                clip_low,