libswscale/swscale.c:1151: error: Uninitialized Value
  The value read from A was never initialized.

libswscale/swscale.c:1151:21: 
1149.             if (CONFIG_SWSCALE_ALPHA && c->alpPixBuf) {
1150.                 YSCALE_YUV_2_RGBX_FULL_C(1<<21, 1)
1151.                     dest[aidx]= A;
                          ^
1152.                     dest[0]= B>>22;
1153.                     dest[1]= G>>22;
