use HAVE_FAST_64BIT

Originally committed as revision 12480 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/rectangle.h

@@ -64,7 +64,7 @@ static av_always_inline void fill_rectangle(void *vp, int w, int h, int stride,
         *(uint32_t*)(p + 3*stride)= v;
     }else if(w==8){
     //gcc can't optimize 64bit math on x86_32
-#if defined(ARCH_X86_64) || (defined(MP_WORDSIZE) && MP_WORDSIZE >= 64)
+#ifdef HAVE_FAST_64BIT
         const uint64_t v= val*0x0100000001ULL;
         *(uint64_t*)(p + 0*stride)= v;
         if(h==1) return;