libswscale/swscale.c:1031: error: Uninitialized Value
  The value read from A was never initialized.

libswscale/swscale.c:1031:21: 
1029.             if (CONFIG_SWSCALE_ALPHA && c->alpPixBuf){
1030.                 YSCALE_YUV_2_RGBX_FULL_C(1<<21, 1)
1031.                     dest[aidx]= A;
                          ^
1032.                     dest[0]= R>>22;
1033.                     dest[1]= G>>22;
