Define HAVE_BIGENDIAN as 0 or 1 according to CPU type

This should replace the inconsistently named and defined
WORDS_BIGENDIAN.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@18873 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -866,6 +866,7 @@ HAVE_LIST="
     alsa_asoundlib_h
     altivec_h
     arpa_inet_h
+    bigendian
     bswap
     closesocket
     cmov