IA64: do not automatically enable hardcoded tables if explicitly disabled

Originally committed as revision 20465 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1807,7 +1807,7 @@ case "$arch" in
         enable fast_64bit
         spic=$shared
         # HACK: currently fails to build if .bss is > 4MB and shared libs are built
-        enabled shared && enable hardcoded_tables
+        enabled shared && enable_weak hardcoded_tables
     ;;
     m68k)
         arch="m68k"