+# check for xlib (only headers needed)
+if [ "x$need_xlib" = "xyes" ]; then
+ check_xlib_headers || fail "please install libx11-dev"
+fi
+
+sizeof_long=`check_define_val __SIZEOF_LONG__`
+if [ "x$sizeof_long" = "x4" ]; then
+ CFLAGS="$CFLAGS -D_FILE_OFFSET_BITS=64"
+fi
+