use C99 standard constant, thanks to Foxy Shadis

Originally committed as revision 5986 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/intfloat_readwrite.c

@@ -27,7 +27,7 @@
 #include "intfloat_readwrite.h"
 
 double av_int2dbl(int64_t v){
-    if(v+v > 0xFFELLU<<52)
+    if(v+v > 0xFFEULL<<52)
         return 0.0/0.0;
     return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075);
 }