Match existing type usage better.

webrtc/common_audio/fft4g.c

 /*
  * http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html
  * Copyright Takuya OOURA, 1996-2001
  *
  * You may use, copy, modify and distribute this code for any purpose (include
  * commercial use) and without fee. Please refer to this package when you modify
  * this code.
  *
  * Changes:
  * Trivial type modifications by the WebRTC authors.
@@ skipping 630 matching lines @@
 
 static void makewt(int nw, int *ip, float *w)
 {
     int j, nwh;
     float delta, x, y;
 
     ip[0] = nw;
     ip[1] = 1;
     if (nw > 2) {
         nwh = nw >> 1;
-        delta = (float)atan(1.0f) / nwh;
+        delta = atanf(1.0f) / nwh;
         w[0] = 1;
         w[1] = 0;
         w[nwh] = (float)cos(delta * nwh);
         w[nwh + 1] = w[nwh];
         if (nwh > 2) {
             for (j = 2; j < nwh; j += 2) {
                 x = (float)cos(delta * j);
                 y = (float)sin(delta * j);
                 w[j] = x;
                 w[j + 1] = y;
                 w[nw - j] = y;
                 w[nw - j + 1] = x;
             }
             bitrv2(nw, ip + 2, w);
         }
     }
 }
 
 
 static void makect(int nc, int *ip, float *c)
 {
     int j, nch;
     float delta;
 
     ip[1] = nc;
     if (nc > 1) {
         nch = nc >> 1;
-        delta = (float)atan(1.0f) / nch;
+        delta = atanf(1.0f) / nch;
         c[0] = (float)cos(delta * nch);
         c[nch] = 0.5f * c[0];
         for (j = 1; j < nch; j++) {
             c[j] = 0.5f * (float)cos(delta * j);
             c[nc - j] = 0.5f * (float)sin(delta * j);
         }
     }
 }
 
 
@@ skipping 627 matching lines @@
         kk += ks;
         wkr = c[kk] - c[nc - kk];
         wki = c[kk] + c[nc - kk];
         xr = wki * a[k] - wkr * a[j];
         a[k] = wkr * a[k] + wki * a[j];
         a[j] = xr;
     }
     a[m] *= c[0];
 }
 #endif  // Not used.