Use emms after I420_UYVY because the OpenGL vout uses floats in the same thread.

Re-enabled i420_yuy2_mmx on Darwin/x86.

configure.ac

@@ -1107,7 +1107,7 @@ SSE_MODULES=""
 ALTIVEC_MODULES="memcpyaltivec i420_yuy2_altivec"
 #ALTIVEC_MODULES="${ALTIVEC_MODULES} idctaltivec motionaltivec"
 
-if test "${enable_gprof}" != "yes" -a "${SYS}" != "darwin"
+if test "${enable_gprof}" != "yes"
 then
   MMX_MODULES="${MMX_MODULES} i420_yuy2_mmx"
 fi

modules/video_chroma/i420_yuy2.c

@@ -390,6 +390,10 @@ static void I420_UYVY( vout_thread_t *p_vout, picture_t *p_source,
         p_line1 += i_dest_margin;
         p_line2 += i_dest_margin;
     }
+
+#if defined (MODULE_NAME_IS_i420_yuy2_mmx)
+    __asm__ __volatile__("emms" :: );
+#endif
 }
 
 /*****************************************************************************