configure: Do not check for libavcore files since it is long gone and…

… xbmc requires ffmpeg 1.0

configure.in

@@ -1603,9 +1603,6 @@ fi
 if test "$use_external_ffmpeg" = "yes"; then
   FFMPEG_LIBNAMES="libavcodec libavfilter libavformat libavutil libpostproc libswscale"
 
-  # libavcore is optional
-  PKG_CHECK_EXISTS([libavcore], FFMPEG_LIBNAMES="$FFMPEG_LIBNAMES libavcore")
-
   # one of libswresample or libavresample is needed
   PKG_CHECK_EXISTS([libswresample], FFMPEG_LIBNAMES="$FFMPEG_LIBNAMES libswresample",
                    [PKG_CHECK_EXISTS([libavresample],
@@ -1634,7 +1631,7 @@ if test "$use_external_ffmpeg" = "yes"; then
   [AC_MSG_ERROR($missing_headers)])])
 
   # optional
-  AC_CHECK_HEADERS([libavcore/avcore.h libavcore/samplefmt.h libavutil/mem.h libavutil/samplefmt.h])
+  AC_CHECK_HEADERS([libavutil/mem.h libavutil/samplefmt.h])
 
   # old FFmpeg have this in libavcodec/opt.h instead:
   AC_CHECK_HEADERS([libavutil/opt.h])