10l: Only set *compose97i *add_yblock to dsputils context if we are building with Snow enabled

Patch by Oded Shimon < ods15 AH ods15 POIS dyndns POIS org >

Originally committed as revision 5175 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dsputil.c

@@ -4048,9 +4048,11 @@ void dsputil_init(DSPContext* c, AVCodecContext *avctx)
     c->try_8x8basis= try_8x8basis_c;
     c->add_8x8basis= add_8x8basis_c;
 
+#ifdef CONFIG_SNOW_ENCODER
     c->vertical_compose97i = ff_snow_vertical_compose97i;
     c->horizontal_compose97i = ff_snow_horizontal_compose97i;
     c->inner_add_yblock = ff_snow_inner_add_yblock;
+#endif
 
 #ifdef HAVE_MMX
     dsputil_init_mmx(c, avctx);